• Research in Plant Disease
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• v.16 no.1
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• pp.48-58
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• 2010

In Korea, EBI fungicides which are highly effective for control of pear scab and rust but of high risk for development of resistance have been frequently sprayed by majority of pear growers. To detect any possible resistance or reduced sensitivity in the field strains of scab fungus to five EBIs, difenoconazole, fluquinconazole, flusilazole, fenarimole and hexaconazole, sensitivity tests were conducted with fungal specimens collected in Ulsan and Naju where scab usually occurs and EBIs have been intensively sprayed for many years. As the strains for which $EC_{50}$ values of the EBIs were largely shifted from those of base-line were occasionally found, the resistant or less sensitive strains were supposed to be distributed. In the activity test for the EBIs by artificial inoculation, in which EBI-treated pear leaves on the potted seedlings were inoculated with fungal spores collected in the two regions, development of resistances to EBIs were confirmed. Since the fungal spores collected at 4 and 2 orchards in Naju and Ulsan, respectively, produced much higher disease incidence on the leaves treated with hexaconazole than those on the untreated control, those fungal specimens were determined as resistant to hexaconazole. Similar results were also obtained with two specimens from Ulsan for flusilazole.

• Journal of Korean Society of Forest Science
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• v.95 no.3
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• pp.358-364
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• 2006

This study was conducted to develop optimal solid culture medium for Tricholoma matsutake. As the solid matrix, granitic soil, perlite, vermiculate, pine sawdust and peat moss were compared regarding their effected on mycelial growth. Ergosterol content which is a fungal wall component was used as the growth index of the mycelia. Among the various solid matrixes, the granitic soil, perlite and mixture of the two supported the growth most. Barely flour appeared to be very effective on the stimulating of the mycelial growth when added to the solid matrix. An mixture of the matrix contained an even (1:1:1:1, v/v/v/v) mixture of granitic soil, perlite, vermiculate and pine sawdust. T. matsutake started growth 2 weeks after inoculation and reached stationary growth phase after 8th weeks in the solid matrix mixture. The mycelial density in the solid matrix was 7 times higher than that in fairy-ring soil. In addition, 30~70% water content and 10% humus soil in the solid matrix also supported good growth suggesting that T. matsutake needs humus soil for a nutrient sources. The solid matrix developed in the present study could be used to study physiological characteristics of T. matsutake as well.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.18-26
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• 2007

Fungicidal screening was performed to control soybean black root rot caused by Calonectria ilicicola through in vitro and greenhouse assays. In in vitro assay, 25 fungicides were assessed by an agar dilution method and a 96-well microtiter plate method. While protective fungicides including dithianon, dichlofluanid, mancozeb, and captan showed a very low activity against the mycelial growth C. ilicicola SC03-15 in the agar dilution method, they displayed potent inhibitory activity against spore germination in a 96-well microtiter plate method with $EC_{50}$ values of 4.65, 0.61, 4.64, and $0.29{\mu}g\;mL^{-1}$, respectively. Ergosterol biosynthesis-inhibiting (EBI) fungicides showed different antifungal activity against mycelial growth and spore germination according to molecules. Difenconazole displayed higher antifungal activity against spore germination rather than mycelial growth, and prochloraz inhibited potently both mycelial growth and spore germination with EC50 values less than $1.8{\mu}g\;ml^{-1}$. In contrast, the other EBI fungicides inhibited more highly mycelial growth than spore germination. Carbendazim+diethofencarb and dazomet also inhibited both mycelial growth and spore germination of C. ilicicola SC03-15 at very low concentrations. In greenhouse assay, carbendazim+diethofencarb effectively controlled a soybean black root rot by drenching 2 days before or after inoculation. In addition, tebuconazole showed potent curative activity against soybean black root rot.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.188-196
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• 1988

Intergeneric or intraspecific protoplast fusion between Saccharomyces cerevisiae X-2180-1A, Candida pseudotropicalis ATCC 8619 and CBS 607 was attempted to produce ethanol from lactose containing materials. Teh intergeneric fusion frequency between Saccharomyces cerevisiae X-2180-1A (ade rho) and Candida pseudotropicalis CBS 607 (his met) was $1.0\times 10^{-5}$. These values exhibited approximately 2-3.5 fold increase when compared with fusion frequency obtained without the treatment of bovine serum albumin, myoinositol and ergosterol, suggesting that these compounds may improve intergeneric of intraspecific protoplast fusion. Nuclear fusion appears to occur in fusants between intergenera(S. cerevisiae+C. pseudotropicalis) and intraspecies (C. pseudotropicalis strains) as strongly suggested by DNA content, nuclear staining, comparison of survival rate to UV light and isolation of recombinants after mitotic segragation. It was also found that alcohol production from intraspecific hybrids was somewhat increased when compared with that from their parents.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.168-176
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• 2008

Recently damage of rice bakanae disease disseminated by infected seeds increased in paddy field in Korea. For controlling rice bakanae disease, the efficacy of 17 fungicides was assessed by 5 kinds of bioassay, spore germination test (SGT), mycelial growth test, detection test on Komada's medium (KDT), pouch test (PT) and greenhouse test (GT). Among ergosterol biosynthesis inhibiting fungicides, prochloraz showed a high controlling activity in all the assay systems while the others showed very low activity except for $500\;{\mu}g/ml$ of hexaconazole in GT and $500\;{\mu}g/ml$ of triflumizole in KDT. Although benomyl and the mixture of benomyl and thiram showed a good activity at 100 and $500\;{\mu}g/ml$ in SGT and PT, respectively, in GT they did a middle activity. Trifloxystrobin and kresoxim-methyl included in strobilurins showed a good activity even at $20\;{\mu}g/ml$ in KDT as well as a middle activity in SGT. Also a high activity not only at $10\;{\mu}g/ml$ in SGT but also at $100\;{\mu}g/ml$ KDT was detected in thiram. The activity of fludioxonil was confirmed in SGT, KDT and PT. Based on these results, it is very important to determine a bioassay system, because the fungicidal activity against rice bakanae disease was fluctuated depending on a assay systems as well as the mechanism of fungicide.

• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.234-247
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• 2021

We used a heterozygous gene deletion library of fission yeasts comprising all essential and non-essential genes for a microarray screening of target genes of the antifungal terbinafine, which inhibits ergosterol synthesis via the Erg1 enzyme. We identified 14 heterozygous strains corresponding to 10 non-essential [7 ribosomal-protein (RP) coding genes, spt7, spt20, and elp2] and 4 essential genes (tif302, rpl2501, rpl31, and erg1). Expectedly, their erg1 mRNA and protein levels had decreased compared to the control strain SP286. When we studied the action mechanism of the non-essential target genes using cognate haploid deletion strains, knockout of SAGA-subunit genes caused a down-regulation in erg1 transcription compared to the control strain ED668. However, knockout of RP genes conferred no susceptibility to ergosterol-targeting antifungals. Surprisingly, the RP genes participated in the erg1 transcription as components of repressor complexes as observed in a comparison analysis of the experimental ratio of erg1 mRNA. To understand the action mechanism of the interaction between the drug and the novel essential target genes, we performed isobologram assays with terbinafine and econazole (or cycloheximide). Terbinafine susceptibility of the tif302 heterozygous strain was attributed to both decreased erg1 mRNA levels and inhibition of translation. Moreover, Tif302 was required for efficacy of both terbinafine and cycloheximide. Based on a molecular modeling analysis, terbinafine could directly bind to Tif302 in yeasts, suggesting Tif302 as a potential off-target of terbinafine. In conclusion, this genome-wide screening system can be harnessed for the identification and characterization of target genes under any condition of interest.

• Journal of Mushroom
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• v.20 no.3
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• pp.119-126
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• 2022

As the importance of public health increases with the spread of infectious diseases, functionality has become a factor affecting consumers' purchase of mushrooms. Therefore, the bioactive components of button mushrooms (Agaricus bisporus), which are generally known to promote button mushroom consumption, were analyzed. White and brown button mushrooms were compared and white beech mushroom (Hypsizygus marmoreus) were used as a control. White button mushrooms had higher sugar and inorganic potassium concentrations than brown button mushrooms, whereas sodium, magnesium, and vitamin C concentrations were not significantly different between the different button mushrooms. Moreover, there was approximately twice as much ergosterol in white button mushrooms than brown button mushrooms. Brown button mushrooms had higher concentrations of 𝛽-glucan and oxalic acid than white button mushrooms, but there was no significant difference in total organic acid content between the two mushroom types. High concentrations of the essential amino acids, ergothioneine, isoleucine, and leucine and the non-essential amino acids, glycine and alanine, were observed. Concentrations of the vitamin B group and total polyphenols were also high.

• Advances in Traditional Medicine
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• v.5 no.4
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• pp.262-271
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• 2005

Cordyceps, one of the most valued traditional Chinese medicines, consists of the dried fungus Cordyceps sinensis growing on the larva of caterpillar. It is also known as 'winter-worm and summer-grass' because of its appearance during different seasons. The parasitic complex of the fungus and the caterpillar is found in soil of a prairie at an elevation of 3,500 to 5,000 meters in northwestern part of China. According to Chinese medicinal theory, Cordyceps is used to replenish the kidney and soothe the lung, and indeed many clinical applications have been reported. The natural Cordyceps is rare and expensive on the local market, and therefore, several mycelial strains have been isolated from natural Cordyceps and manufactured in large quantities by fermentation technology, and they are commonly sold as health food products in Orient. The adulterants of Cordyceps are commonly found on the market, and therefore the authentication of these products has to be defined. Having the urgent need from current market, different chemical markers such as nucleoside, ergosterol, mannitol and polysaccharide are being used for quality control of Cordyceps. Unfortunately, these markers are far from optimization, and therefore extensive works are needed to define the pharmacological efficiency of these markers.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.164-169
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• 2007

ln our continued search for biologically active compounds from traditional medicine, we found that ethyl acetate fraction from Inonotus obliquus showed potent antioxidant activities on three different cell-free bioassay systems. Bioassay-directed chromatographic fractionation of the ethyl acetate fraction from Inonotus obliquus afforded four phenolic compounds, 4-(3,4-dihydroxyphenyl)-(E)-3-buten-2-one (1) , 3,4-dihydroxybenzaldehyde (2), protocatechuic acid (3) and caffeic acid (4) along with three sterols such as lanosterol (5), ergosterol peroxide (6) and 9,11-dehydroergosterol peroxide (7). Among isolates, phenolic compounds (1-4) were assessed for antioxidant activities. Almost phenolic compounds showed potent DPPH and superoxide anion radicals scavenging and lipid peroxidation inhibitory activities indicating that these phenolic compounds contribute to the antioxidative activities of I. obliquus. Compounds 2-3 and 7 were isolated for the first time from this plant.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.319-325
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• 2009

Twelve compounds were isolated from the 70% ethanol extract of Lonicera Caulis (Caprifoliaceae) and their structures were identified as six triterpenoids [(24S)-cycloart-25-en-$3{\beta}$,24-diol (1), pomolic acid (7), ursolic acid (8), euscaphic acid (9), hederagenin (10), and 23-hydroxytormentic acid (12)] and six sterols [obtusifoliol (2), gramisterol (3), citrostadienol (4), ${\beta}$-sitosterol (5), ergosterol peroxide (6) and ${\beta}$-sitosterol glucoside (11)]. The chemical structures of these compounds were identified on the basis of spectroscopic methods and comparison with literature values. All the compounds were isolated from this plant parts for the first time.