• 동의생리병리학회지
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• 제20권4호
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• pp.799-806
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• 2006

Fungi cause a number of plant and animal diseases. Because fungi are more chemically and genetically similar to animals than other organisms, this makes fungal diseases very difficult to treat. Human fungal infections are uncommon in normally healthy persons, being confined to conditions such as candidiasis (thrush) and dermatophyte skin infections such as athlete's foot. However, in the immunocompromised host, a variety of normally mild or nonpathogenic fungi can cause potentially fatal infections. Furthermore, the relative ease with which people can now visit 'exotic' countries provides the means for unusual fungal infections to be imported into this country. Fungal infections or mycoses are classified depending on the degree of tissue involvement and mode of entry into the host. These are Cutaneous, Subcutaneous, Systemic, and Opportunistic. As listed above, in superficial mycoses infection is localised to the skin, the hair, and the nails. An example is 'ringworm' or 'tinea', an infection of the skin by a dermatophyte. Ringworm refers to the characteristic central clearing that often occurs in dermatophyte infections of the skin. Dermatophyte members of the genera Trycophyton, Microsporum and Epidermophyton are responsible for the disease. Tinea can infect various sites of the body, including the scalp (tinea capitis), the beard (tinea barbae) the foot (tinea pedis: 'athlete's foot') and the groin (tinea cruris). All occur in the United Kingdom although tinea infections, other than pedis, are now rare. Candids albicans is a yeast causing candidiasis or 'thrush' in humans. As a superficial mycoses, candidiasis typically infects the mouth or vagina. C. albicans is part of the normal flora of the vagina and gastrointestinal tract and is termed a 'commensal' However, during times of ill health or impaired immunity the balance can alter and the organism multiplies to cause disease. Antibiotic treatment can also alter the normal bacterial flora allowing C. albicans to flourish. If we study mycoses of the orient medicine, we can improve the medical skills about mycoses.

• Infection and chemotherapy
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• 제50권4호
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• pp.362-366
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• 2018

Millerozyma farinosa (formerly Pichia farinosa) is halotolerant yeast mainly found in food and ubiquitous in the environment. It was a rare yeast pathogen, but it has recently emerged as a cause of fungemia in immunocompromised patients. Optimal therapy for invasive fungal infection by this pathogen remains unclear. We report a case of catheter related blood stream infection caused by M. farinosa in a 71-year-old patient who recovered successfully after removal of the central venous catheter and treatment with micafungin.

• Mycobiology
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• 제40권4호
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• pp.231-235
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• 2012

Fungal endophytes are microfungi that live in plants without causing apparent symptoms of infection. This study was conducted to identify endophytic fungi isolated from leaves of coniferous trees in Bohyeon Mountain of Korea. We collected leaves of two species of coniferous trees, Pinus densiflora and Pinus koraiensis, from 11 sites in the study area. A total 58 isolates were obtained and identified using molecular and morphological characteristics. Four species of endophytic fungi were isolated from P. densiflora: Lophodermium conigenum, Leotiomycetes sp., Septoria pini-thunbergii, and Polyporales sp., while two fungal species were isolated from P. koraiensis: Eurotiomycetes sp. and Rhytismataceae sp. The most frequently isolated species were L. conigenum and S. pini-thunbergii.

• Mycobiology
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• 제36권1호
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• pp.10-12
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• 2008

In recent years, there has been a rapid decrease in amphibian populations worldwide, and infectious diseases have been associated with this decline. Diseased frogs inhabiting Korea were collected from fields, and the diseases were identified by morphological and molecular analyses. Two fungal diseases-saprolegniasis and chromomycosis-were detected in the frogs. Saprolegniasis caused by Saprolegnia spp. was found in Rana plancyi chosenica from Gangwon-do and Rana huanrenensis from Chungbuk. Chromomycosis, which is caused by infection with Cladosporium cladosporioides, was detected in Rana catesbeiana from Busan.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.9-9
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• 2014

Null mutants generated by targeted gene replacement are frequently used to reveal function of the genes in fungi. However, targeted gene deletions may be difficult to obtain or it may not be applicable, such as in the case of redundant or lethal genes. Constitutive expression system could be an alternative to avoid these difficulties and to provide new platform in fungal functional genomics research. Here we developed a novel platform for functional analysis genes in Magnaporthe oryzae by constitutive expression under a strong promoter. Employing a binary vector (pGOF1), carrying $EF1{\beta}$ promoter, we generated a total of 4,432 transformants by Agrobacterium tumefaciens-mediated transformation. We have analyzed a subset of 54 transformants that have the vector inserted in the promoter region of individual genes, at distances ranging from 44 to 1,479 bp. These transformants showed increased transcript levels of the genes that are found immediately adjacent to the vector, compared to those of wild type. Ten transformants showed higher levels of expression relative to the wild type not only in mycelial stage but also during infection-related development. Two transformants that T-DNA was inserted in the promotor regions of putative lethal genes, MoRPT4 and MoDBP5, showed decreased conidiation and pathogenicity, respectively. We also characterized two transformants that T-DNA was inserted in functionally redundant genes encoding alpha-glucosidase and alpha-mannosidase. These transformants also showed decreased mycelial growth and pathogenicity, implying successful application of this platform in functional analysis of the genes. Our data also demonstrated that comparative phenotypic analysis under over-expression and suppression of gene expression could prove a highly efficient system for functional analysis of the genes. Our over-expressed transformants library would be a valuable resource for functional characterization of the redundant or lethal genes in M. oryzae and this system may be applicable in other fungi.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2002년도 추계학술대회
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• pp.40-50
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• 2002

Fruit fly, Drosophila melanogaster has developed efficient immune mechanisms to prevent microbial infection, which are consisted of cellular and humoral responses. During the systemic or local infection, two distinct pathways (Toll and Imd) play major roles in antimicrobial peptide synthesis. The Toll pathway is required to defend Gram-positive bacterial and fungal infections, whereas the Imd pathway is important in Gram-negative bacterial infection. We have shown that the infection of the opportunistic Gram-negative bacterium, Pseudomonas aeruginosa strain PA14 (PA14) into fly dorsal thorax can kill the flies within 48 h ($100\%$ mortality) in our optimized infection condition, suggesting that the PA14 strain can cause disease progress in fly model system. We found that flies carrying a constitutively activated mutant form of the Toll receptor $(Tl^{10b})$ showed increased resistance to P. aeruginosa infection and that flies carrying mutations in the Toll signaling pathway as well as in the Imd signaling pathway was more susceptible to PA14 infection. All these results imply that the Toll pathway might be important in the resistance to this pathogenic Gram-negative bacterial infection.

• 식물병연구
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• 제23권3호
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• pp.278-282
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• 2017

옥수수는 세계에서 가장 많이 재배되는 곡물 중 하나이며 중요한 식량자원이다. 생산 된 옥수수는 수확 및 건조 후에 저장되는데 저장 옥수수의 질을 떨어뜨리는 곰팡이 감염 및 곰팡이 독소는 생육 시기부터 저장기간 내내 발생한다. 이 연구는 우리나라에서 2015년 수확하여 1년정도 저장한 옥수수를 대상으로 옥수수의 크기와 변색 정도에 따른 감염 곰팡이 종과 독소검출을 조사하였다. 데옥시니발레놀과 제랄레논이 아플라톡신, 오크라톡신, 푸모니신, 티투독소보다 상대적으로 높은 수준으로 검출되었는데 특히, 데옥시니발레놀 경우 작은 낱알에서 $1200{\pm}610{\mu}g/kg$로 검출되었는데, 이는 이보다 큰 낱알에서 검출된 독소 함량에 비해 4배에서 6배까지 많은 양이 검출되었으며, 변색된 낱알의 혼입으로 인해 데옥시니발레놀, 제랄레논 및 푸모니신의 함량이 증가하였다. 곰팡이의 경우 Fusarium, Aspergillus 그리고 Penicillium 속 등 총 10종이 분리되었다. 이중 F. graminearum은 정상적인 낱알에 비해 변색 된 붉은색 낱알과 갈색 낱알에서 60%와 40%로 높은 빈도로 검출되었다. 따라서 수확 후 변색 또는 손상된 옥수수 낱알이 정상 낱알에 섞여 보관될 경우, 손상된 낱알에 오염되어 있던 병원균이 정상 낱알을 감염하여 진균 독소의 발생이 증가할 수 있으므로 오염 낱알의 제거가 곰팡이 및 독소의 오염 예방에 도움이 될 것이다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 춘계학술대회 및 임시총회
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• pp.13-13
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• 2015

Rice blast fungus, Magnaporthe oryzae, is the most destructive pathogen of rice in the world. This fungus has a biotrophic phase early in infection and switches to a necrotrophic lifestyle after host cell death. During the biotrophic phase, the fungus competes with host for nutrients and oxygen. Continuous uptake of oxygen is essential for successful establishment of blast disease of this pathogen. Here, we report transcriptional responses of the fungus to oxygen limitation. Transcriptome analysis using RNA-Seq identified 1,047 up-regulated genes in response to hypoxia. Those genes were involved in mycelial development, sterol biosynthesis, and metal ion transport based on hierarchical GO terms and well-conserved among three different fungal species. In addition, null mutants of three hypoxia-responsive genes were generated and tested for their roles on fungal development and pathogenicity. The mutants for a sterol regulatory element-binding protein gene, MoSRE1, and C4 methyl sterol oxidase gene, ERG25, exhibited increased sensitivity to hypoxia-mimetic agent, increased conidiation, and delayed invasive growth within host cells, suggesting important roles in fungal development. However, such defects did not cause any significant decrease in disease severity. The other null mutant for alcohol dehydrogenase gene, MoADH1, showed no defect in the hypoxia-mimic condition and fungal development. Taken together, this comprehensive transcriptional profiling in response to a hypoxia condition with experimental validations would provide new insights on fungal development and pathogenicity in plant pathogenic fungi.

• The Plant Pathology Journal
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• 제26권1호
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• pp.8-16
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• 2010

The phytopathogenic fungus Magnaporthe oryzae is a major limiting factor in rice production. To understand the genetic basis of M. oryzae pathogenic development, we previously analyzed a library of T-DNA insertional mutants of M. oryzae, and identified ATMT0879A1 as one of the pathogenicity-defective mutants. Molecular analyses and database searches revealed that a single TDNA insertion in ATMT0879A1 resulted in functional interference with an annotated gene, MGG00056, which encodes a short-chain dehydrogenase/reductase (SDR). The mutant and annotated gene were designated as $MoSDR1^{T-DNA}$ and MoSDR1, respectively. Like other SDR family members, MoSDR1 possesses both a cofactor-binding motif and a catalytic site. The expression pattern of MoSDR1 suggests that the gene is associated with pathogenicity and plays an important role in M. oryzae development. To understand the roles of MoSDR1, the deletion mutant ${\Delta}Mosdr1$ for the gene was obtained via homology-dependent gene replacement. As expected, ${\Delta}Mosdr1$ was nonpathogenic; moreover, the mutant displayed pleiotropic defects in conidiation, conidial germination, appressorium formation, penetration, and growth inside host tissues. These results suggest that MoSDR1 functions as a key metabolic enzyme in the regulation of development and pathogenicity in M. oryzae.

• The Plant Pathology Journal
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• 제32권1호
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• pp.53-57
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• 2016

Major diseases in grafted cacti have been reported and Fusarium oxysporum, Bipolaris cactivora, Phytophthora spp. and Collectotrichum spp. are known as causal pathogens. These pathogens can lead to plant death after infection. Therefore, some European countries have quarantined imported cacti that are infected with specific fungal pathogens. Consequently, we developed PCR detection methods to identify four quarantined fungal pathogens and reduce export rejection rates of Korean grafted cacti. The pathogen specific primer sets F.oF-F.oR, B.CF-B.CR, P.nF-P.nR, and P.cF-P.CR were tested for F. oxysporum, B.cactivora, P. nicotinae, and P. cactorum, respectively. The F.oF-F.oR primer set was designed from the Fusarium ITS region; the B.CF-B.CR and P.nF-P.nR primers respectively from Bipolaris and Phytophthora ITS1; and the P.cF-P.CR primer set from the Ypt1protein gene region. The quarantine fungal pathogen primer pairs were amplified to the specific number of base pairs in each of the following fungal pathogens: 210-bp (F. oxysporum), 510-bp (B. cactivora), 313-bp (P. nicotinae), and 447-bp (P. cactorum). The detection limit for the mono- and multiplex PCR primer sets was 0.1 ng of template DNA under in vitro conditions. Therefore, each primer set successfully diagnosed contamination of quarantine pathogens in export grafted cacti. Consequently, our methodology is a viable tool to screen contamination of the fungal pathogen in exported grafted cacti.