• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.11-11
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• 2014

Fungal pathogens have huge impact on health and economic wellbeing of human by causing life-threatening mycoses in immune-compromised patients or by destroying crop plants. A key determinant of fungal pathogenesis is their ability to undergo developmental change in response to host or environmental factors. Genetic pathways that regulate such morphological transitions and adaptation are therefore extensively studied during the last few decades. Given that epigenetic as well as genetic components play pivotal roles in development of plants and mammals, contribution of microbial epigenetic counterparts to this morphogenetic process is intriguing yet nearly unappreciated question to date. To bridge this gap in our knowledge, we set out to investigate histone modifications among epigenetic mechanisms that possibly regulate fungal adaptation and processes involved in pathogenesis of a model plant pathogenic fungus, Magnaporthe oryzae. M. oryzae is a causal agent of rice blast disease, which destroys 10 to 30% of the rice crop annually. Since the rice is the staple food for more than half of human population, the disease is a major threat to global food security. In addition to the socioeconomic impact of the disease it causes, the fungus is genetically tractable and can undergo well-defined morphological transitions including asexual spore production and appressorium (a specialized infection structure) formation in vitro, making it a model to study fungal development and pathogenicity. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Histone modifying enzymes were identified applying a search pipeline built upon profile hidden Markov model (HMM) to proteomes. The database incorporates 22,169 histone-modifying enzymes identified from 342 species including 214 fungal, 33 plants, and 77 metazoan species. The dbHiMo provides users with web-based personalized data browsing and analysis tools, supporting comparative and evolutionary genomics. Based on the database entries, functional analysis of genes encoding histone acetyltransferases and histone demethylases is under way. Here I provide examples of such analyses that show how histone acetylation and methylation is implicated in regulating important aspects of fungal pathogenesis. Current analysis of histone modifying enzymes will be followed by ChIP-Seq and RNA-seq experiments to pinpoint the genes that are controlled by particular histone modifications. We anticipate that our work will provide not only the significant advances in our understanding of epigenetic mechanisms operating in microbial eukaryotes but also basis to expand our perspective on regulation of development in fungal pathogens.

• Journal of Chest Surgery
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• 제37권3호
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• pp.292-296
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• 2004

효모균은 전 세계적으로 도처에 분포하고 있는 곰팡이로서, 특히 비둘기 배설물에 의해 오염된 토양에 존재한다. 폐의 효모균증은 건강한 사람에게는 잘 발생하지 않으며 면역이 저하된 환자 특히 후천성 면역결핍증 환자에게서 호발한다. 일반적으로 증상이 없이 흉부엑스선상 고립성 또는 다발성 폐결절이 관찰되며, 절제된 조직에서의 병리학적 소견으로 진단된다. 기침이나 객담, 발열 및 무력감 등의 급성폐렴의 증상을 보일 수 있으나 질병특유의 증상은 아니다. 효모균증은 대부분의 곰팡이 염색에 의해 진단되며, 증상이 없는 고립성 폐결절을 포함하여 진단된 모든 효모균증에 있어서 약물치료를 시행한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제20권2호
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• pp.152-157
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• 1998

Disturbances of the interrelationship among the host, environment, microorganism will cause the infection clinically. Infection can be classified into bacterial, viral, fungal origin, Bacterial infection is most common due to dental caries, periodontal disease. These infections have the potential to spread via the fascial spaces in the head and neck region. We have undertaken clinical studies on infections in the oral and maxillofacial regions by analyzing 78 hospitalized patients in the Dept. of Oral and Maxillofacial Surgery, Dong-A University Hospital from 1994 to 1997. The results were as fellows; l. Odontogenic infections were most common with the incidence of 84.6%. 2. Considering the number of involved space, single space was 83.3%, double or more space was 16.6%. The most common fascial space involved was submandibular space and followed by buccal space, 3. The most causative organism isolated from the pus cultures was streptococci group 35.4%. 4. Antibiotics were administrated in all cases, and surgical incision and drainage was performed in 87.2%. 5. Combined administration of penicillin and aminoglycoside was most common in 34.6%.. 6. 7 cases were diagnosed as Ludwig's angina and tracheostomy was done in 2 cases of them.

• The Plant Pathology Journal
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• 제17권3호
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• pp.128-140
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• 2001

Infection of pepper leaves by Colletotrichum cocodes at the two- and eight-leaf stages caused susceptible and resistant lesions 96 h after inoculation, respectively. At the two-leaf stage, progressive symptom development occurred on the infected leaves. In contrast, localized necrotic spots were characteristic symptoms at the eight-leaf stage. Infected leaves at the two-leaf stage exhibited cell death accompanied by the accumulation of autofluorescent compounds. At the eight-leaf stage, pepper leaves infected by the anthracnose fungus displayed localized autofluorescence from the symptoms. Infection of pepper leaves by C. cocodes at the two-leaf stage resulted in its rapidand massive colonization of all the leaf tissues including the vascular tissue, together with cytoplasmic collapse, distortion of chloroplasts, and disruption of host cell walls. However, penetration of C. cocodes was very limited in the older leaf tissues of pepper plants at the eight-leaf stage. Fungal hyphae grew only in the intramural spaces of the epidermal cell walls at this stage. Occlusion of amorphous material in xylem vessels, aggregation of fibrillar material in inter-cellular spaces, and deposition of protein bodies were found as resistance responses to C. cocodes.

• 식물병연구
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• 제8권1호
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• pp.45-49
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• 2002

딸기탄저병의 발병특성은 정식 직후 격발하다가 시간이 지날수록 발병율이 감소하였으며, 11월 이후에는 발병이 감소하였다. 정식 직후에는 주로 런너로 침입하였으나 엽병 제거 후는 제거한 상처부위로 주로 침입을 하였다. 식물체의 부위별로는 런너에서 가장 강한 병원력을 보였으며 접종방법별로는 생장점 부위로 관주를 할 경우 가장 발병율이 높았다. 딸기탄저병에 의해 고사된 포기를 제거한 자리에 건전한 포기를 심었을 경우 옮겨 심은 포기에서는 발병이 되지 않았다.

• The Plant Pathology Journal
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• 제39권2호
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• pp.181-190
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• 2023

The fungal pathogen Pseudocercospora fuligena, known to affect tomatoes in the tropics and subtropics, has been reported from temperate climates including the United States and Turkey in recent years. In this study, an isolate from fresh tomatoes and the disease it causes were characterized and infection mechanisms investigated. Macroscopically, both sides of tomato leaves show indistinct effuse patches but prolific production of fuliginous lesions is conspicuous on the abaxial side first but also on the adaxial side later on as infection progressed. Microscopically, fascicles of conidiophores (11-128 ㎛ × 3.5-9 ㎛) arising from stromata and conidia with up to 12 septations were observed. Molecular characterization of the isolate revealed high homology (99.8%) to other P. fuligena isolated from tomatoes in Turkey. Out of the 10 media tested, P. fuligena grew significantly well and sporulated better on unsealed tomato oatmeal agar and carrot leaf decoction agar, both supplemented with CaCO₃. Direct transfer of conidia from profusely sporulating lesions was the easiest and quickest method of isolation for in-vitro studies. Light and scanning electron microscopy on cleared and intact tomato leaves further confirmed stomatal penetration and egress as well as prevalence of primary and secondary infection hyphae. In situ, blocked stomatal aperture areas of 154, 401, and 2,043 ㎛² were recorded at 7, 12, and 17 days after inoculation, respectively. With the recent expanded horizon of the pathosystem and its consequential impact, such studies will be useful for a proper diagnosis, identification and management of the disease on tomato worldwide.

• The Plant Pathology Journal
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• 제30권4호
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• pp.343-354
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• 2014

Rice blast disease caused by Magnaporthe oryzae is one of the most serious diseases of cultivated rice (Oryza sativa L.) in most rice-growing regions of the world. In order to investigate early response genes in rice, we utilized the transcriptome analysis approach using a 300 K tilling microarray to rice leaves infected with compatible and incompatible M. oryzae strains. Prior to the microarray experiment, total RNA was validated by measuring the differential expression of rice defense-related marker genes (chitinase 2, barwin, PBZ1, and PR-10) by RT-PCR, and phytoalexins (sakuranetin and momilactone A) with HPLC. Microarray analysis revealed that 231 genes were up-regulated (>2 fold change, p < 0.05) in the incompatible interaction compared to the compatible one. Highly expressed genes were functionally characterized into metabolic processes and oxidation-reduction categories. The oxidative stress response was induced in both early and later infection stages. Biotic stress overview from MapMan analysis revealed that the phytohormone ethylene as well as signaling molecules jasmonic acid and salicylic acid is important for defense gene regulation. WRKY and Myb transcription factors were also involved in signal transduction processes. Additionally, receptor-like kinases were more likely associated with the defense response, and their expression patterns were validated by RT-PCR. Our results suggest that candidate genes, including receptor-like protein kinases, may play a key role in disease resistance against M. oryzae attack.

• The Plant Pathology Journal
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• 제21권4호
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• pp.322-327
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• 2005

Regression models for determining infection periods of apple white rot were developed based on conidial germination and appressorium formation of Botryosphaeria dothidea. A total of 120 apple fruits were inoculated with the fungal conidial suspension and subjected to 6 temperatures and 10 wetness periods. Conidia germinated and produced appressoria, exhibiting swollen tips of germ tubes on the fruit surface. Conidial germination (G) increased with temperature (T) and wetness period (W), and was described as $G=-89.273+7.649T+7.056W-0.109T^{2}-0.085W^{2}-0.066TW(R^{2}=0.75)$. Less than 2 hr of wetness period were enough for conidia to germinate at 25 to $30^{\circ}C$. Effects of temperature and wetness period on appressorium formation (A) could be explained as $A=-1.540-2.375W+0.045W^{2}+0.213TW(R^{2}=0.77)$. The relationship between conidial germination and appressorium formation ($A_g$) was described as$A_g=0.381-0.227G+0.005G^{2}(R^{2}=0.67)$, suggesting that conidial germination may have to reach approximately $43.7\%$ to initiate appressorium formation. Using the regression equation for conidial germination and the criterion of $43.7\%$ conidial germination, an infection model was developed to determine infection periods based on temperature and wetness period. The infection model with the criterion of $43.7\%$ conidial germination was apparently more conservative than the appressorium formation model in determining possibility of apple infection. The infection model seemed sensitive to variable weather conditions, suggesting possible use of the model for timing fungicide sprays to control white rot of apples in practice.

• Journal of Mycology and Infection
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• 제23권4호
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• pp.99-104
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• 2018

Background: Trichophyton verrucosum (T. verrucosum) is a zoophilic dermatophyte that causes ringworm in cattle and is prevalent worldwide. This dermatophyte may be responsible for various conditions, especially inflammatory skin lesions. Objective: In this study, we aimed to investigate the changes in the clinical and epidemiological characteristics of T. verrucosum infections in southeastern Korea. Methods: A total of 34 patients who visited the Catholic Skin Clinic and the Kyungpook National University Hospital in Daegu, Korea from 2005 to 2017 were diagnosed with T. verrucosum infection. The diagnosis was confirmed using fungal culture. The data were based on a retrospective survey of the medical records. Results: The annual incidence of T. verrucosum infection was very low. There was no difference in the sexual incidence. T. verrucosum infection was most common among subjects in their fifties and sixties. The highest incidence was during the month of September. The arm was most frequently involved, followed by the face. This infection was predominant in patients living in rural areas. Conclusion: These clinicoepidemiological findings provide useful information for understanding the changes in the infection caused by T. verrucosum. In particular, it was interesting to note that the incidence was very low, majority of the affected subjects were in their fifties and sixties, and the most commonly affected site was the arm.

• Mycobiology
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• 제46권3호
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• pp.242-253
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• 2018

Onion (Allium cepa L.) is one of the major vegetable crops in Korea that are damaged and lost by pathogenic fungal infection during storage due to a lack of proper storage conditions. The aim of this study was to determine an appropriate control measure using thymol to increase the shelf life of onions. To control fungal infections that occur during low-temperature storage, it is necessary to identify the predominant fungal pathogens that appear in low-temperature storage houses. Botrytis aclada was found to be the most predominant fungal pathogen during low-temperature storage. The antifungal activity of the plant essential oil thymol was tested and compared to that of the existing sulfur treatments. B. aclada growth was significantly inhibited up to 16 weeks with spray treatments using a thymol solution. To identify an appropriate method for treating onions in a low-temperature storage house, thymol was delivered by two fumigation treatment methods, either by heating it in the granule form or as a solution at low-temperature storage conditions (in vivo). We confirmed that the disease severity was reduced up to 96% by fumigating thymol solution compared to the untreated control. The efficacy of the fumigation of thymol solution was validated by testing onions in a low-temperature storage house in Muan, Jeollanam-do. Based on these results, the present study suggests that fumigation of the thymol solution as a natural preservative and fungicide can be used as an eco-friendly substitute for existing methods to control postharvest disease in long-term storage crops on a commercial scale.