• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1806-1816
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• 2019

Candida albicans is an opportunistic fungus possessing multiple virulence factors controlling pathogenicity. Cell wall proteins are the most important among these factors, being the first elements contacting the host. Ddr48 is a cell wall protein consisting of 212 amino acids. A DDR48 haploinsufficient mutant strain was previously found necessary for proper oxidative stress response and drug resistance. In this study, we aimed to further elucidate the role of Ddr48 by performing additional phenotypic characterization assays. A combinatory proteomic and bioinformatics approach was also undertaken to determine differentially expressed cell wall proteins. Results showed that the mutant strain exhibited a 10% decrease in adhesion mirrored by a 20% decrease in biofilm formation, and slight sensitivity to menadione, diamide, and SDS. Both strains showed similar hyphae formation, virulence, temperature tolerance, and calcofluor white and Congo red sensitivities. Furthermore, a total of 8 and 10 proteins were identified exclusively in the wild-type strain grown under filamentous and non-filamentous conditions respectively. Results included proteins responsible for superoxide stress resistance (Sod4 and Sod6), adhesion (Als3, Hyr4, Pmt1, and Utr2), biofilm formation (Hsp90, Ece1, Rim9, Ipp1, and Pra1) and cell wall integrity (Utr2 and Pga4). The lack of detection of these proteins in the mutant strain correlates with the observed phenotypes.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.306-311
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• 2013

Pythium blight occurred by Pythium aphanidermatum on chewing fescue cv. "Jamestowm II" from early June, 2010 and 2011 at the test field in Daegu University in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass were leaf blights dying from the leaf tip and root rot, which appeared patches of brown to dark brown color or gray brown color in the field. The pathogens (40-1 isolate) of Pythium blight was isolated from the diseased leaf and crown tissue and cultured on potato-dextrose agar (PDA) for identification. Lobulate sporangia were inflated, complex structures, and filamentous sporangia were usually indistinguishable from vegetative hyphae. Sequences of ribosomal RNA gene of the fungus were homologous with similarity of 100% to those of P. aphanidermatum isolates in GenBank database. Pathogenicity was also confirmed on the chewing fescue, creeping betgrass and Kentucky bluegrass by Koch's postulates. This is the first report of Pythium blight on chewing fescue caused by P. aphanidermatum in Korea.

• The Korean Journal of Mycology
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• v.42 no.2
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• pp.97-103
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• 2014

A total of 7039 strains of filamentous fungi are preserved in Korean Agricultural Culture Collection (KACC). The 4065 strains (58%) of them, which produce many spores in cultivation on proper media, are preserved with freeze-drying method. They are also preserved with liquid nitrogen and deep-freezer storage in order to minimize loss by death. Aspergillus, Penicillium, Lichtheimia, Mucor, Rhizopus, etc. which are common in surrounding environments, are included in this category. The others which do not produce spores, or produce few spores in vitro, are preserved with liquid nitrogen, deep-freezer and mineral oil storage. Phytophthora, Pythium, Cercospora, Septoria, Rhizoctonia, etc. are included in this category. The authors also introduced various fungal preservation methods and provided detailed preservation procedures that are used in KACC.

• The Korean Journal of Mycology
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• v.38 no.2
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• pp.160-166
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• 2010

A homothallic filamentous fungus Aspergillus nidulans has been used as the a model organism for studying growth and development for eukaryotic system. Various studies about specific transcription factors have been performed for elucidating the molecular mechanisms of growth, asexual and sexual developmental processes. Among them, the fkhE gene (AN2025.3) is located in chromosome VII and contains an ORF encoding 718 amino acid polypeptide intervening with two short introns. The cDNA sequencing revealed that at least four types of alternative splicing events were occurred when the fkhE gene was transcribed. The putative FkhE polypeptide contains a conserved forkhead domain and a bipartite nuclear localization signal at it's N-terminus and C-terminus, respectively. Deletion of fkhE resulted in impaired conidiophore formation in a solid medium. However, the sexual developmental process or cleistothecia formation was normal. Furthermore, fkhE deletion mutant produced conidiophores and conidia under the submerged culture, indicating that the fkhE gene is involved in asexual developmental process similar to the fkhF gene.

• KSBB Journal
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• v.17 no.4
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• pp.381-387
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• 2002

A filamentous fungus, strain FB01 showing high $\beta$-glucosidase activity was isolated from a compost. This fungus was cocultured with Trichoderma viride to enhance the productivity of $\beta$-glucosidase by changing inoculation time of the fungus. The microbial consortium showed higher cellulolytic enzyme production than T. viride alone. The maximal enzyme production was obtained when the microbial consortium was cultured at 30$\^{C}$ and pH 6.0 for 10 days with the activities of CMCase, $\beta$-glucosidase, and avicelase of 2.0, 0.8, and 0.2 U/mL, respectively. These enzyme activities were 2, 4, and 2 times as high as those of CMCase, p-glucosidase, avicelase from T. viride, respectively, indicating that a synergistic interaction appeared between T. viride and strain FBOI . The serial subcultures with pH control increased $\beta$-glucosidase production about 3.2 times. Enzyme production using ricestraw as a carbon source showed that the activities of CMCase, $\beta$-glucosidase, and avicelase were 3.69, 0.76, 0.17 U/mL, respectively, and $\beta$-glucosidase activity was 1.5 times higher than that of T viride.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.1019-1030
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• 2003

The study was conducted to isolate and identify highly fibrolytic anaerobic fungi from the guts of a Hanwoo steer and a Korean native goat, and then investigate the characterization of cellulolytic activity of an anaerobic fungus. Twenty-one anaerobic fungal colonies were isolated in the study, in which 16 colonies were isolated from the rumen contents of the Hanwoo steer and 5 colonies from the duodenal fluids of the Korean native goat. Four anaerobic fungi were selected based on higher cellulolytic enzyme activities to identify under a optical microscope. NLRI-M003 and -T004 belong to Neocallimastix genus and NLRI-M014 belongs to Piromyces genus based on the morphology of their thallus, sporangia, rhizoid and the number of flagella. NLRI-M001 appeared to be an unknown strain of anaerobic fungi due to its different morphology from existing types of anaerobic fungi, though the morpholgoy is similar to Orpinomyces sp. Supplementation of 2% anaerobic fungal culture(NLRI-M003) in rumen-mixed microorganisms increased in vitro DM degradability of rice straw and filter paper up to 4 and 11%, respectively, compared with non-supplementation(control). CMCase and xylanase activities in in vitro culture were also higher in 2% fungal supplementation than controls in both rice straw and filter paper substrates.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.172-176
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• 2002

A filamentous microorganism, strain FJ1, was isolated from completely rotten wood for the production of cellulolytic enzymes. For the production of the enzymes, cellulolsic wastes were used as carbon sources of strain FJ1 and rice straw showed higher enzyme activities than sawdust and pulp. The activities of CMCase, xylanase, $\beta$-glucosidase, and avicelase were 2.95, 5.89, 0.45, and 0.12 unit/ml by use of rice straw, respectively. To enhance production of the enzymes, the mixture substrate of rice straw and cellulosic materials were investigated as carbon sources. The highest activities of CMCase, $\beta$-glucosidase, and avicelase were found in the mixture of rice straw (0.5%, w/v) and avicel (0.5%, w/v), and the highest xylanase was obtained at the mixture ratio of 0.71%(w/v) and 0.29%(w/v). Addition of 0.1%(w/v) peptone showed enhanced production of the cellulolytic enzymes in which the activities of CMCase, xylanase, $\beta$-glucosidase, and avicelase were 19.23, 27.18, 1.28, and 0.53 unit/ml, respectively. The production of the enzymes using rice straw was efficiently induced in the presence of avicel and pulp containing cellulose. In particular, a medium composed of rice straw (0.5%, w/v) and pulp (0.5%, w/v) yielded larger cellulolytic enzymes: CMCase 24.3 unit/ml, xylanase 38.7 unit/ml, $\beta$-glucosidase 1.5 unit/ml, and avicelase 0.6 unit/ml. The filamentous microorganism, strain FJ1 utilized various cellulosic wastes as carbon sources and will be expected as a favorable candidate for biological saccharification of cellulosic wastes.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.131-142
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• 2008

Magnaporthe oryzae, the causal agent of the rice blast disease, poses a worldwide threat to stable rice production. The large-scale functional characterization of genes controlling the pathogenicity of M. oryzae is currently under way, but little is known about heat shock protein 40 (Hsp40) function in the rice blast fungus or any other filamentous plant pathogen. We identified 25 genes encoding putative Hsp40s in the genome of M. oryzae using a bioinformatic approach, which we designated M. oryzae heat shock protein forty (MHF 1-25). To elucidate the roles of these genes, we characterized the functions of MHF16 and MHF21, which encode type ill and type n Hsp40 proteins, respectively. MHF16 and MHF21 expression was not significantly induced by heat shock, but it was down-regulated by cold shock. Knockout mutants of these genes $({\Delta}$mhf16 and ${\Delta}$mhf21) were viable, but conidiation was severely reduced. Moreover, sectoring was observed in the ${\Delta}mhf16$ mutant when it was grown on oatmeal agar medium. Conidial germination, appressorium formation, and pathogenicity in rice were not significantly affected in the mutants. The defects in conidiation and colony morphology were fully complemented by reintroduction of wild type MHF16 and MHF21 alleles, respectively. These data indicate that MHF16 and MHF21 play important roles in conidiation in the rice blast fungus.

• 한국균학회소식:학술대회논문집
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• 2018.05a
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• pp.11-11
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• 2018

Cryphonectria parasitica, chestnut blight fungus, has a characteristic of decreasing pathogenicity when infected with Cryphonectria hypovirus 1. C. parasitica is known to be one of the most representative model systems used to observe the interaction between viruses, plants and fungi. The mitogen-activated protein kinase (MAPK) pathway, which is well conserved in various organisms ranging from yeast to humans, functions in relaying phosphorylation-dependent signals within MAPK cascades to diverse cellular functions involved in the regulation of pheromone, cell wall integrity, and osmotolerance in filamentous fungi. Several genes in the MAPK pathway were revealed to be regulated by hypovirus, or to be involved in pathogenicity in C. parasitica. Among these pathways, the CWI pathway has aroused interest because CpBck1, an ortholog of yeast Bck1 (a CWI MAPKKK), was previously reported to be involved in cell wall integrity and sectorization. Interestingly, sporadic sectorization was observed in the CpBck1 mutant and sectored phenotypes were stably inherited in the progeny that were successively transferred from sectored mycelia. In this study, we analyzed the biological function of CpSlt2, downstream gene of CpBck1, to confirm whether the sectorization phenomenon occurred in the specific single gene or cell wall integrity (CWI) pathway. As results, the CpSlt2-null mutant exhibited marked changes in colonial growth, near absence of conidiation and aerial hyphae, abnormal pigmentation, CWI-related phenotypic defects, and dramatically impaired virulence. As cultivation of the mutant strains progressed, the majority of the colonies showed sporadic sectorization and mycelia from the sectored area stably maintained the sectored phenotype. These results suggest that the unique sectorization is CWI pathway-specific, though the components in the same CWI pathway have common and specific functions.

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.39-39
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• 2014

In a homothallic filamentous fungus Aspergillus nidulans, sexual and asexual developments are largely affected by the genetic and environmental factors. To regulate the complex subsets of genes involved in the developmental processes accurately, tight regulations of transcription factors are required. The forkhead type transcription factors are the class of regulators that function in a broad spectrum of cellular and developmental processes in many species from yeast to human. Here, we identified the fkhA and fkhB genes that encode a conserved forkhead transcription factors. The fkhA deletion resulted in the complete loss of fruiting body formation under all conditions favoring sexual development, suggesting that the fkhA gene is required for sexual development in A. nidulans. Overexpression of fkhA resulted in enhanced formation of fruiting bodies under induction condition not only in the normal condition but also in the condition of presence of 0.6 M KCl, which strongly inhibits sexual development. To know the function of the fkhB gene, we also generated fkhB knock-out strain in A. nidulans. Deletion of fkhB resulted in abnormal conidiophore formation under standard conditions and delayed sexual development process, suggesting that the fkhB gene plays an important role in conidiophore morphogenesis Taken together, these results suggest that the fkhA gene is necessary and sufficient for regulating sexual development and the fkhB gene is a transcription factor related in asexual developmental process in A. nidulans.