• 한국응용곤충학회지
• /
• 제40권1호
• /
• pp.51-58
• /
• 2001

동충하초로 불리우는 곤충병원진균(Paecilomycesjaponicus)이 의약적으로 상품화되어 사용되고 있으며,누에(Bombyxmori)가 이 진균의 최적 기주로 선발되어 자실테 생산에 이용되고 있다. 현재 이 균주의 처리는 갓 탈피한 누에 5령 유충에 접종하고 고온(30\"C),다습(약 90%상대 습도)및 24시간 절식 조건에서 스트레스에 의한 면역 저하를 유도하여 균주 접종율을 높히는 방식을 취하고 있다. 본 연구는 면역반응 중개에 중요한 eicosanoid반응을 억제시키는 dexamethas-one(DEX)을 이용하여 물리적 스트레스 환경의 조성 없이도 누에에 면역 저하를 유도시키려는 목적으로 수행되었다. 누에 $\lrcorner$령 유충에 주입된 DEX(1007g)는 병원진균의 혈구치사 능력을 뚜렷 이 증가시켰다. 또 DEX(1007g)는 작은혹형성이나 피막형성에서 나타나는 혈구응집 반응이나, phenoloxidase활성으로 측정된 누에의 세포성 면역 반응을 뚜렷이 저하시켰다 효과적 병원진균 의 충체 처리를 위해 곤충체의 부착 능력을 제고시켜 접종율을 높히는 것으로 본 연구에서 판명된 Triton-X(0.05%)를 모든 충체 처리 용액에 이용되었다. DEX(100$\mu\textrm{g}$)단독처리가 기존의 물리 적 스트레스 환경 처리를 통한 방법과 유사한 수준으로 병원진균의 접종율을 나타냈다. 본 연구는 DEX가 동충하초 접종율을 제고시킬 수 있음을 시사했고, 누에는 이러한 진균 병원체에 대해 서 eicosanoid를 이용하여 세포성 면역을 발현하는 것으로 제시하고 있다.고 있다.

• 대한의생명과학회지
• /
• 제24권3호
• /
• pp.175-182
• /
• 2018

Aspergillosis is a life-threatening disease in individuals with compromised immune systems. Fungal invasion is a highly critical process during host cellular infection. Several papers have reported that transcription factors are responsible for the infection process. To investigate what transcription factors are involved in the process in an effort to inhibit fungal infection into cells, I checked the surfactant protein family and PU.1 transcription factor levels in A549 cells infected with A. fumigatus conidia. PU.1 and surfactant protein-D levels were reduced in cells infected with fungal conidia. I then observed an increase in surfactant protein-D on PU.1-overexpressed cells. Infection of A. fumigatus conidia was decreased in PU.1-overexpressed cells, whereas the suppression of PU.1 did not lead to any changes in cases of A. fumigatus conidia infection. These results indicate that PU.1 inhibits the infection of A. fumigatus conidia via the expression of surfactant protein-D, suggesting that PU.1 is a key transcription factor for protection against A. fumigatus invasion.

• The Plant Pathology Journal
• /
• 제39권3호
• /
• pp.275-289
• /
• 2023

Fungal isolates from infected Chinese quince trees were found to cause black rot in Yeongcheon, Gyeongsangbuk Province, Korea. The quince leaves withered and turned reddish-brown and fruits underwent black mummification. To elucidate the cause of these symptoms, the pathogen was isolated from infected leaf and fruit tissues on potato dextrose agar and Levan media. Several fungal colonies forming a fluffy white or dark gray mycelium and two types of fungi forming an aerial white mycelium, growing widely at the edges, were isolated. Microscopic observations, investigation of fungal growth characteristics on various media, and molecular identification using an internal transcribed spacer, β-tubulin, and translation elongation factor 1-α genes were performed. The fungal pathogens were identified as Diplodia parva and Diplodia crataegicola. Pathogenicity tests revealed that the pathogen-inoculated fruits exhibited a layered pattern, turning brown rotting; leaves showed circular brown necrotic lesions. The developed symptoms were similar to those observed in the field. Fungal pathogens were reisolated to fulfill Koch's postulates. Apples were inoculated with fungal pathogens to investigate the host range. Strong pathogenicity was evident in the fruits, with browning and rotting symptoms 3 days after inoculation. To determine pathogen control, a fungicidal sensitivity test was conducted using four registered fungicides. Thiophanate-methyl, propineb, and tebuconazole inhibited the mycelial growth of pathogens. To the best of our knowledge, this is the first report on the isolation and identification of the fungal pathogens D. parva and D. crataegicola from infected fruits and leaves of Chinese quince, causing black rot disease in Korea.

• The Plant Pathology Journal
• /
• 제21권4호
• /
• pp.310-316
• /
• 2005

The objectives of this study were to identify the aecial host ranges of four Korean Gymnosporangium species, G. asiaticum, G. cornutum, Gjaponicum and Gyamadae, and to verify the morphological characteristics of telia as diagnostic keys to the species. Thirteen Korean Rosaceous woody species were artificially inoculated with teliospores obtained from Juniperus species. There was high specificity between telial and aecial hosts and the fungal species, providing the first experimental proof on host alternation of these rust fungi in Korea. Telia on the witches' broom and on the small galls were identified as new telial characteristics in G asiaticum and in G. yamadae, respectively. Aecial hosts of G. asiaticum and G. yamadae showed varying responses in their susceptibility and in the days required for formation and duration of spermogonia and aecia after inoculation. Four telial host species in Juniperus were confirmed for the first time in Korea, which include J. chinensis var. kaizuka, J. chinensis var. horizontalis and J. chinensis var. globosa for G. asiaticum; and J. chinensis var. kaizuka for G. yamadae.

• Mycobiology
• /
• 제42권2호
• /
• pp.152-157
• /
• 2014

The iron uptake and utilization pathways play a critical role in allowing human pathogens, including Cryptococcus neoformans, the causative agent of fatal meningoencephalitis, to survive within the mammalian body by competing with the host for iron. Here we show that the iron regulon is also required for diverse environmental stress responses and that in C. neoformans, it is regulated by the high-osmolarity glycerol response (HOG) pathway. Between CFO1 and CFO2, two ferroxidase genes in the iron regulon, CFO1 but not CFO2 was induced during oxidative and osmotic stress. Interestingly, we found that the HOG pathway repressed basal expression of both CFO1 and CFO2. Furthermore, when the HOG pathway was blocked, CFO2 also responded to oxidative and osmotic stress and the response of CFO1 was increased. We also established that CFO1 plays a major role in responding and adapting to diverse environmental stresses, including oxidative and genotoxic damage, osmotic fluctuations, heavy metal stress, and stress induced by cell membrane destabilizers. Therefore, our findings indicate that in C. neoformans, the iron uptake and utilization pathways are not only required for iron acquisition and survival, but also play a significant role in the environmental stress response through crosstalk with the HOG pathway.

• Journal of Microbiology and Biotechnology
• /
• 제20권3호
• /
• pp.630-636
• /
• 2010

A survey of the endangered orchid Orchis militaris populations was carried out in north-eastern Italy. The occurrence of fungal root endophytes was investigated by light and electron microscopies and molecular techniques. Two main sites of presence were individuated in the Euganean Hills, differing as to the percentage of flowering individuals and of capsules completing maturity. Fluorescence microscopy revealed an intracellular cortical colonization by hyphal pelotons. Two ITS PCR products co-amplified. Sequencing revealed for the former an identity and a high similarity (99%) with a Tulasnellaceae (Basidiomycota) fungus found within tissues of the same host in independent studies in Hungary and Estonia, suggesting an interesting case of tight specificity throughout the Eurosiberian home range. The second amplicon had 99% similarity with Tetracladium species (Ascomycota) recently demonstrated as potential endophytes. TEM revealed two different hyphal structures. Double fungal colonization appears to occur in Orchis militaris and the possible requirement of a specific fungal partner throws light on the causes of this plant's rarity and threatened status.

• 한국균학회소식:학술대회논문집
• /
• 한국균학회 2015년도 추계학술대회 및 정기총회
• /
• pp.14-14
• /
• 2015

Cellular aspects of sooty mold on walnut leaves were investigated by using light and electron microscopy. A black coating developed on the adaxial leaf surface of a walnut tree. No infestations were found on the abaxial leaf surface with peltate glandular trichomes. Light microscopy showed that fungal complexes from the leaf surface were composed of brown conidia and hyphae. Conidia, with longitudinal and transverse septa, were variable in length ranging from 10 to $30{\mu}m$, and commonly found in clusters, forming microsclerotia. Neither epidermal penetration nor hyphal entrance to host tissues was observed. Based on their morphological characteristics, the fungal complexes were assumed to be Capnodium species. An electron-dense melanized layer was present on the cell wall of multi-celled conidia. Concentric bodies in the fungal cytoplasm had an electron-translucent core surrounded by an electron-dense margin with a fibrillar sheath. Chloroplasts without starch granules in the palisade mesophyll cells of sooty leaves had electron-dense stromata and swollen plastoglobuli. These results suggest that the epiphytic growth of fungal complexes can be attributed to the melanized layer and concentric bodies against a water-deficient environment on the leaf surface. Ultrastructural characteristics of the sooty leaves indicate typical features of dark-adapted and non-photosynthetic shade leaves.

• 한국응용곤충학회지
• /
• 제50권3호
• /
• pp.195-201
• /
• 2011

한국산 균식성 거저리가 서식하는 숙주버섯의 종류 및 기주와의 관계를 정리하였다. 대부분의 한국산 균식성 거저리는 담자균강 가운데 민주름버섯류를 숙주버섯으로 선택하였다. 한국산 균식성 거저리는 모두 4개족(가시거저리족, 뿔거저리족, 뾰족날개거저리족, 르위스거저리족) 31종으로 조사되었으며, 이 균식성 종들이 각각 서식하는 숙주버섯은 모두 42종으로 파악되었다. 한국 전역에 분포하는 31종의 균식성 거저리 목록과 균식성 거저리의 숙주버섯 목록을 제공하였다. 각 목록은 성충과 애벌레의 숙주버섯 이용 양상을 토대로 작성되었는데, 균식성 거저리의 약 62%가 균의존형(obligate mycetobionts)으로 밝혀졌다.

• Journal of Species Research
• /
• 제13권2호
• /
• pp.111-126
• /
• 2024

Korean bamboo forests encompass 22,067 hectares and are dominated by Phyllostachys species. These forests serve as vital ecosystems, providing nourishment and habitat for diverse flora, fauna, and microorganisms. Among these inhabitants, various fungal species have been documented worldwide, displaying ecological roles as saprobes, parasites, and symbionts within or outside the bamboo host. However, a comprehensive study of bambusicolous fungi within the Korean bamboo ecosystem remains a critical gap in our knowledge. In this study, we conducted an extensive survey of bamboo materials collected from various bamboo forests and subsequently undertook fungal isolation. Primary identification of bambusicolous fungi was achieved through analysis of the internal transcribed spacer (ITS) region. As a result, we identified seven previously unrecorded bambusicolous fungal species (Fusarium bambusarum, Fusicolla violacea, Macroconia gigas, Neopestalotiopsis camelliae-oleiferae, Neopestalotiopsis iberica, Neopestalotiopsis longiappendiculata, and Thyridium punctulatum). Phylogenetic analysis using protein-coding genes appropriate for each taxon and morphological observation were conducted to ensure accurate identification. This study contributes to our understanding of fungal diversity within bamboo forests in Korea.

• 한국균학회소식:학술대회논문집
• /
• 한국균학회 2016년도 춘계학술대회 및 임시총회
• /
• pp.13-13
• /
• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.