• 한국해양생명과학회지
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• 제7권2호
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• pp.121-128
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• 2022

L-asparaginase (ASNase) is a therapeutic enzyme used to treat acute lymphoblastic leukemia. Currently, the most widely used ASNases are originated from bacteria. However, owing to the adverse effects of bacterial ASNases, new resources for ASNase production should be explored. Fungal enzymes are considered efficient and compatible resources of natural products for diverse applications. In particular, fungal species belonging to the genus Trichoderma are well-known producers of several commercial enzymes including cellulase, chitinase, and xylanase. However, enzyme production by marine-derived Trichoderma spp. remains to be elucidated. While screening for extracellular ASNase-producing fungi from marine environments, we found four strains showing extracellular ASNase activity. Based on the morphological and phylogenetic analyses using sequences of translation elongation factor 1-alpha (tef1α), the Trichoderma isolates were identified as T. afroharzianum, T. asperellem, T. citrinoviride, and Trichoderma sp. 1. All four strains showed different ASNase activities depending on the carbon sources. T. asperellem MABIK FU00000795 showed the highest ASNase value with lactose as a carbon source. Based on our findings, we propose that marine-derived Trichoderma spp. are potential candidates for novel ASNase production.

• Mycobiology
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• 제34권3호
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• pp.138-142
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• 2006

Soil cyanobacteria isolated from the rice paddy fields of 10 different locations across Korea were evaluated by agar plate diffusion test for antifungal activity. Aqueous, petroleum ether, and methanol extracts from one hundred and forty two cyanobacterial strains belonging to the 14 genera were examined for antifungal properties against seven phytopathogenic fungi causing diseases in hot pepper (Capsicum annuum L). Of total cyanobacteria, nine cyanobacteria (6.34%) exhibited antifungal effects. The nine cyanobacteria selected with positive antifungal activities were two species of Oscillatoria, two of Anabaena, three of Nostoc, one of Nodularia, and one of Calothrix. Alternaria alternata and Botrytis cinerea were inhibited by nine and eight species of cyanobacteria, respectively. Rhizopus stolonifer was suppressed by only methanol extract of Nostoc commune FK-103. In particular, Nostoc commune FK-103 and Oscillatoria tenuis FK-109 showed strong antifungal activities against Phytophthora capsici. Their antifungal activity at the late exponential growth phase is related to the growth temperature and not associated with the growth parameters such as cell biomass and $chlorophyll-{\alpha}$ concentration. The high inhibition levels of antibiotics were 22.5 and 31.8 mm for N. commune FK-103 and O. tenuis FK-109, respectively. The optimal temperature for antibiotic productivity was $35^{\circ}C$.

• The Plant Pathology Journal
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• 제24권1호
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• pp.1-7
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• 2008

Fusarium verticillioides (teleomorph Gibberella moniliformis) is associated with maize worldwide causing ear rot and stalk rot, and produces fumonisins, a group of mycotoxins detrimental to humans and animals. While research tools are available, our understanding of the molecular mechanisms associated with fungal virulence and fumonisin biosynthesis in F. verticillioides is still limited. One of the restraints that hampers F. verticillioides gene characterization is the fact that homologous recombination (HR) frequency is very low (<2%). Screening for a true gene knock-out mutant is a laborious process due to a high number of ectopic integrations. In this study, we generated a F. verticillioides mutant (SF41) deleted for FvKU70, a gene directly responsible for non-homologous end-joining mechanism, with the aim of improving HR frequency. Here, we demonstrate that FvKU70 deletion does not impact key Fverticillioides phenotypes, e.g., development, secondary metabolism, and virulence, while dramatically improving HR frequency. Significantly, we also confirmed that a high percentage (>85%) of the HR mutant strains harbor a desired mutation with no additional copy of the mutant allele inserted in the genome. We conclude that SF41 is suitable for use as a type strain when performing high-throughput gene function studies in F. verticillioides.

• 농약과학회지
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• 제5권4호
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• pp.33-39
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• 2001

물달개비에 병을 일으키는 Pythium myriotylum 균주를 2000년 충청남도 유성 지역에서 수집한 시료로부터 분리하였으며, 실험실과 온실에서 생물학적 방제제로서의 가능성을 조사하였다. 이 곰팡이는 넓은 온도 범위에서 잘 자랐으며 특히 생장적온은 $35^{\circ}C$ 이었다. 또한 $30{\sim}35^{\circ}C$에서 물달개비에 강한 병원성을 나타냈다. 여뀌바늘, 알방동사니, 사마귀풀, 올챙이고랭이 등의 논잡초에는 병원성이 강하였으나, 강피에는 병을 일으키지 못하였다. 벼에 대한 생육시기별 및 품종에 따른 병 발생을 조사한 결과, 발아 직후의 벼는 생육에 저해를 받았으나 1엽기 이상의 벼는 영향을 받지 않았다. 또한 12 품종의 $3{\sim}4$엽기 벼도 MD2에 의하여 영향을 받지 않았다. 그리고 배추, 옥수수, 콩 등 12종의 작물에 대한 병원성 실험을 실시하였는데, 밀을 제외한 11종의 작물은 영향이 없었다. 이상의 결과로부터 Pythium myriotylum MD2는 1엽기 이상의 벼에 대하여 선택성이 있으며, 물달개비뿐만 아니라 여러 종류의 일년생 논잡초에 대하여 강한 병원성을 보이고 또한 작물에 대한 영향도 적어서 생물적 방제제로서 가능하리라 생각되었다.

• 생약학회지
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• 제33권3호통권130호
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• pp.219-223
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• 2002

In order to screen new radical scavenging principle which is expected to be antiaging drug lead, we have isolated 160 strains of the marine-derived fungi and investigated 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity for their acetone extracts. The significant activities (>50% Inhibition) were observed in 8 strains of fungi (MFA006, MFA0l4, MFA040, MFA133, MFA139, MFA143, MFA148, MFA153), and among them, MFA153 (Aspergillus parasiticus) showed the most significant radical scavenging activity. The active components were purified by assay-guided isolation to yield two known benzyl alcohols, l53B3 (1) and l53B4 (2), and their structures were determined by physicochemical evidence. Two compounds (1,2) showed the significant radical scavenging activity with $IC_{50}$ values of 0.6 and $1.4{\mu}M$ against DPPH, respectively.

• 한국균학회지
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• 제49권4호
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• pp.441-454
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• 2021

Fungal diseases including anthracnose, stem rot, blight, wilting, and root rot of crops are caused by phytopathogens such as Colletotrichum species, Sclerotinia sclerotiorum, Phytophthora species, and Fusarium oxysporum and F. solani which threaten the production of chili pepper. In this study, to identify biological control agents (BCAs) of phytopathogenic fungi, potentially useful Bacillus species were isolated from the field soils. We screened out five Bacillus strains with antagonistic capacity that are efficiently inhibiting the growth of phytopathogenic fungi. Bacillus species were characterized by the production of extracellular enzymes, siderophores, and indole-3-acetic acid (IAA). Furthermore, the influence of bacterial strains on the plant growth promoting activity and seedling vigor index were assessed using Brassica juncea as a model plant. Inoculation with Bacillus subtilis SRCM 121379 significantly increased the length of B. juncea shoots and roots by 45.6% and 52.0%, respectively. Among the bacterial isolates, Bacillus subtilis SRCM 121379 showed the superior enzyme activities, antagonistic capacity and plant growth promoting effects. Based on the experimental results, Bacillus subtilis SRCM 121379 (GenBank accession no. NR027552) was finally selected as a BCA candidate.

• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1078-1089
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• 2017

Biofilm formation of Staphylococcus aureus is one of its mechanisms of drug resistance. Anti-biofilm screening of 106 compounds from marine-derived fungi displayed that 12 compounds inhibited S. aureus biofilm formation by >50% at the concentration of $100{\mu}g/ml$, and only secalonic acid D (SAD) and B inhibited by >90% at $6.25{\mu}g/ml$ without inhibiting cell growth after 24-h incubation. Meanwhile, it was found that the double bond between C-1 and C-10 of citrinin derivatives and the C-C connection position of two chromone monomers may be important for their anti-biofilm activities. Moreover, SAD slightly facilitated biofilm eradication and influenced its architecture. Furthermore, SAD slowed the cell growth rate in the preceding 18-h incubation and differentially regulated transcriptional expression of several genes, such as agr, isaA, icaA, and icaD, associated with biofilm formation in planktonic and biofilm cells, which may be the reason for the anti-biofilm activity of SAD. Finally, SAD acted synergistically against S. aureus growth and biofilm formation with other antibiotics. These findings indicated that various natural products from marine-derived fungi, such as SAD, could be used as a potential biofilm inhibitor against S. aureus.

• Mycobiology
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• 제37권1호
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• pp.53-61
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• 2009

The process of biodegradation in lingo-cellulosic materials is critically relevant to biospheric carbon. The study of this natural process has largely involved laboratory investigations, focused primarily on the biodegradation and recycling of agricultural by-products, generally using basidiomycetes species. In order to collect super white rot fungi and evaluate its ability to degrade lingo-cellulosic material, 35 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye. In the laccase enzymatic analysis chemical test, 33 white rot fungi and 2 brown rot fungi were identified. The degradation ability of polycyclic aromatic hydrocarbons (PAHs) according to the utilized environmental conditions was higher in the mushrooms grown in dead trees and fallen leaves than in the mushrooms grown in humus soil and livestock manure. Using Poly-R 478 dye to assess the PAH-degradation activity of the identified strains, four strains, including Agrocybe pediades, were selected. The activities of laccase, MnP, and Lip of the four strains with PAH-degrading ability were highest in Pleurotus incarnates. 87 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye on solid media. Using Poly-R 478 dye to assess the PAHdegrading activity of the identified strains, it was determined that MKACC 51632 and 52492 strains evidenced superior activity in static and shaken liquid cultures. Subsequent screening on plates containing the polymeric dye poly R-478, the decolorization of which is correlated with lignin degradation, resulted in the selection of a strain of Coriolus versicolor, MKACC52492, for further study, primarily due to its rapid growth rate and profound ability to decolorize poly R-478 on solid media. Considering our findings using Poly-R 478 dye to evaluate the PAH-degrading activity of the identified strains, Coriolus versicolor, MKACC 52492 was selected as a favorable strain. Coriolus versicolor, which was collected from Mt. Yeogi in Suwon, was studied for the production of the lignin-modifying enzymes laccase, manganese-dependent peroxidase (MnP), and lignin peroxidase (LiP).

• 한국균학회지
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• 제20권4호
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• pp.347-353
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• 1992

국내에서 자생하고 있는 75균주의 고등균류를 액체배양하여 얻은 다당류를 $CCl_4$에 의해 독성이 유발된 초대배양 간세포에 가하여 간세포 독성에대한 다당류의 보호효과를 glutamic pyruvate transaminase(GPT)활성을 측정하여 검색한 결과는 다음과 같다. 75균주의 고등균류 중 간세포 보호효과를 나타낸 것은 60균주로 Ganoderma lucidum 15균주 중 13균주, Lentinus edodes 7균주 중 5균주, Pleurotus ostereatus 1균주, Coriolus versicolor 5군주 중 4균주, Lyophyllum spp. 2균주, Grifori frondosa 7균주, Agaicus spp. 3균주, Schizophyllum commune 16균주 중 14균주, Cordyceps spp. 18균주 중 11균주등이었다. 상기 고등균류 중 GPT활성이 80%이하로 나타나, 비교적 간세포 보호효과가 우수한 것은 Ganoderma lucidum IY003 및 IY009, Lentinus edodes IY103, Lyophyllum sp. IY402, Agaicus sp. IY701 및 IY703, Schizophyllum commune IY804, IY810 및 IY818, Cordyceps sp. IY902등 10균주였으며, 이들의 GPT활성은 각각 80.0%, 75.5%, 78.2%, 75.2% 73.6%, 75.0%, 75.1%, 77.7%, 77.5% 및 78.4%로 나타났다.

• 한국미생물·생명공학회지
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• 제50권2호
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• pp.202-210
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• 2022

Aflatoxin contamination in rice has been documented in a number of studies, and has a high incidence in Asian countries, and as such, there has been a growing interest in alternative biocontrol strategies to address this issue. In this study, 147 strains of yeasts and yeast-like fungi were screened for their potential to produce volatile organic compounds (VOCs) active against Aspergillus flavus strains that produce aflatoxin B₁ (AFB₁). Five strains within four different genera showed greater than 50% growth inhibition of some strains of A. flavus. These were Anthracocystis sp. DMKU-PAL124, Aureobasidium sp. DMKU-PAL120, Aureobasidium sp. DMKU-PAL144, Rhodotorula sp. DMKU-PAL99, and Solicococcus keelungensis DMKU-PAL84. VOCs produced by these microorganisms ranged from 4 to 14 compounds and included alcohols, alkenes, aromatics, esters and furans. The major VOCs produced by the closely related Aureobasidium strains were found to bedistinct. Moreover, 2-phenylethanol was the most abundant compound generated by Aureobasidium sp. DMKU-PAL120, while methyl benzeneacetate was the major compound emitted from Aureobasidium sp. DMKU-PAL144. On the other hand, 2-methyl-1-butanol and 3-methyl-1-butanol were significant compounds produced by the other three genera. These antagonists apparently inhibited A. flavus sporulation and mycelial development. Additionally, the reduction of the AFB1 in the fungal-contaminated rice grains was observed after co-incubation with these VOC-producing strains and ranged from 37.7 ± 8.3% to 60.3 ± 3.4%. Our findings suggest that these same microorganisms are promising biological control agents for use against aflatoxin-producing fungi in rice and other agricultural products.