• Journal of the Mineralogical Society of Korea
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• v.22 no.2
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• pp.153-162
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• 2009

The main compositions of "Seokganju", a Korean traditional red mineral pigment, are iron oxides. To investigate its mineralogical and functional properties, we had got its ore from Juto cave in Ulreoung island, which was a famous field of it in Korean documents. The ore occurs as a paleosol between the olivine basalt and amphibole trachyte in discontinuously. It is reddish brown and yellowish brown and consists mainly of clay minerals with minor debris. Its reddish and yellowish brown color are due to the hematite and ferrihydrate, respectively. These iron oxides are precipitated as ferrihydrate from the ferrous water in the paleosol and partly changed to hematite. The color reproduced in timber by using seokganju pigment with traditional tools and methods is similar to that in heritage building. The moistureproofing and fire resistance of Ulreungdo seokganju is far better than that of artificial seokganju. Moreover, the combustion tests show that the artificial seokganju promote the ignition and combustion of the timber. Ulreungdo seokganju is regarded as a pigment with fungicidal efficacy because growth of two wood decay fungi (cov. and typ.) are inhibited in solid medium with it.

• Journal of the Korean Wood Science and Technology
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• v.28 no.1
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• pp.65-70
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• 2000

Ergosterol is an indicator chemical of fungi and involves in fungal cell growth as a major component in fungal cell membranes. Thus, this chemical can be used to estimate live fungal biomass within various solid substrates. Ergosterol content in liquid culture of Lentinula edodes had a linear relationship (r=0.98) with the hyphal mass of the fungus. This chemical content differed depending on the fungal strains, age of culture and water content levels of sawdust substrate. Ergosterol content was 0.13% in the 10 weeks old liquid culture while it was 0.10% in 20 weeks old one. The chemical content in the sawdust cultures of the fungus varied 0.015% to 0.042% depending upon strains and water content levels within sawdust substrate. Ergosterol content in the culture of a L. edodes strain, Sanrim 4, was higher by $20{\mu}g$ to $140{\mu}g$/g dry substrate than those of strains, Mok-H and Sanrim 6. And the chemical contents in the sawdust cultures with 125% or 175% water, 297 to 425 ${\mu}g$/g dry substrate, were higher than those with 75% or 225% water, 148 to $286{\mu}g$/g dry substrate. We conclude that ergosterol analysis can estimate the fungal biomass within solid substrate such as logs and sawdust.

• Journal of Sericultural and Entomological Science
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• v.41 no.1
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• pp.36-40
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• 1999

The optimal condition for the production of the artificial fruiting bodies of Paecilomyces japonica in bulk was determined from the observation of the conidial, hyphal, and cultural condition and the medium. The colony was grown 32 mm diameter in 14 days on potato dextrose agar(PDA). Conidia was irregularly long oval-shaped and measured 4.07${\times}$1.56 ${\mu}$m in average. The hyaline hyphae formed transparent bundles which branched out. The fruiting body on the insect surface was measured 30 to 50 mm in length and formed up to 55 branches. Potato dextrose(PD) both was the most effective for the growth of Paecilomyces japonica among the liquid type media. About 3.1 mg mrcelia in dry weight were produced in 50 ml/PD broth. The best condition for the production of conidia under which condition 4.3${\times}$10$^8$ conidia/ml were harvested was pH 5.0 in acidity and 20$^{\circ}C$ following preculture at 24$^{\circ}C$ in temperature for 7 days.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.326-332
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• 2008

Various bacteria were isolated from Korean soil samples based on their capability inhibiting the growth of MRSA strains. Among them, strain YK5 with the highest activity was a Gram positive sporulative bacillus with motility. It did not produce indole and no acid was formed from mannitol by the bacterium. The 16S rRNA sequence of the strain showed $95{\sim}98%$ homology with those of Paenibacillus spp.. The bacterial isolate shared the highest homology with that of P. elgii (98%), but was named as Paenibacillus incheonensis YK5 due to differences in physiological properties. Butanol extract of the P. incheonensis YK5 culture grown in SST medium at $37^{\circ}C$ for 96 hr showed a broad antimicrobial activity against Gram-positive (MRSA and Streptococcus pneumoniae) and negative (Pseudomonas aeruginosa, Salmonella spp., Shigella spp., Escherichia coli, Klebsiella pneumoniae) pathogenic bacteria and fungi (Cryptococcus neoformans and Trichophyton). The antimicrobial activity in the crude extract was stable in a broad range of temperature and pH, $20{\sim}100^{\circ}C$ and $3.0{\sim}6.0$, respectively. Therefore, the antimicrobial activity of P. incheonesis YK5 had potential as a novel antibiotics for pathogens including MRSA.

• Research in Plant Disease
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• v.23 no.3
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• pp.256-261
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• 2017

The effects of insecticide and fungicide treatment were investigated to reduce mycotoxin contamination of corn (Zea mays L.) seeds. Deoxynivalenol and zearalenone contents were reduced in the treated seeds, but aflatoxin, ochratoxin A, fumonisin, and T-2 toxin were not effective by chemical treatments. The chemical treatment did not affect the growth of saprophyte, but inhibited the pathogenic fungi such as Fusarium verticillioides, F. graminearum and F. equiseti. Myotoxin contents at different harvesting time were compared. As the harvest time was delayed, both levels of deoxynivalenol and zearalenone and frequency of Fusarium spp. increased. However, the major nutrient contents of corn seeds were not affected by harvesting period. These results show that chemical treatments are necessary to reduce the fungal contamination of corn and harvest without delay is important as well.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.17-23
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• 2013

Candida biofilms are organized microbial communities growing on the surfaces of host tissues or indwelling medical devices, and the biofilms show enhanced resistance against the conventional antifungal agents. The roots of Coptidis chinensis have been widely used for medicinal purposes in East Asia. The present study was aimed to assess the effect of C. chinensis aqueous extract upon preformed biofilms of 10 clinical Candida albicans isolates and the antifungal activities which contribute to inhibit the C. albicans biofilm formation. Its effect on preformed biofilms was judged using XTT [2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide)] reduction assay, and metabolic activity of all tested strains was reduced significantly ($57.3{\pm}14.7%$) at $98{\mu}g/ml$ of the C. chinensis extract. The extract damaged the cell membrane of C. albicans which was analyzed by fluorescein diacetate and propidium iodide staining. The anticandidal activity was fungicidal, and the extract obstructed the adhesion of C. albicans biofilms to polystyrene surfaces, arrested C. albicans cells at $G_o/G_1$ as well, and reduced the growth of biofilms or budding yeasts finally. The data suggest that C. chinensis has multiple antifungal effects on target fungi resulting in preventing the formation of biofilms. Therefore, C. chinensis holds great promise for exploring antifungal agents from natural products in treating and eliminating biofilm-associated Candida infection.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.1-8
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• 1993

Extruded defatted soy flour (DSF) with twin screw extruder was compared with steam treated DSF for soy sauce fermentation. Independent variables of response surface methodology (RSM) for extrusion were barrel temperature $(145{\sim}165^{\circ}C)$, feed moisture content $(25{\sim}35%)$, and feed rate $(20{\sim}30\;kg/hr)$. Extrusion conditions for production of the extrudates having highest water absorption capacity, lowest bulk density and highest expansion ratio were obtained by regression analysis of each dependent variable. Electron photomicrographs revealed significant increase of porosity inside the koji made from extruded DSF. Therefore, growth of fungi inside the koji made from extrudates of DSF was accelerated to achieve higher activities of protease, ${\alpha}-amylase$, and glucoamylase compared to the koji made from steamed DSF. Although amino acid composition of soy sauces prepared from two different DSF did not show any significant difference, the content of free amino acids in soluble nitrogen compounds was higher $(13%{\pm}2)$ in soy sauce made from extruded SDF. During the whole period of fermentation color of soy sauce made from extrudates of DSF was darker. Sensory evaluation did not reveal any serious off-odor and off-taste in the soy sauce fermented from extruded DSF.

• Journal of Korean Society of Forest Science
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• v.65 no.1
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• pp.43-47
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• 1984

Pinus rigida ${\times}$ P. taeda seedlings in a nursery was inoculated with basidiospores of Pisolithus tinctorius (Pt) either collected from Suweon, Korea or introduced from U.S.A. to compare the effectiveness of the spores from two different origins as mycorrhizal inocula. Nursery beds were fumigated with methyl bromide and 1g of spores was used to inoculate $1m^2$ of soil surface just before seed sowing. Seedlings inoculated with American Pt (#250 strain from Georgia, U.S.A.) were 15% taller than Korean Pt at the end of the first growing season. The seedlings from fumigation treatment only (no inoculation involved) was slightly taller (statistically unsignificant) than those with Korean Pt, but slightly smaller than those with American Pt. In a subsequent year experiment, the seedlings inoculated with American and Korean Pt after soil fumigation were 66% and 60% taller, respectively, than seedlings infected by natural fungi without soil fumigation, suggesting the dual effects of Pt and fumigation on the seedling growth. Therefore potential of Pt spores for an effective inoculum exists and selection of Pt strains which have adapted to specific local environments is needed to develop better sources of mycorrhizal inocula.

• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.49-53
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• 2010

Disease control efficacy was evaluated with use of Bacillus subtilis KB-401 against cucumber powdery mildew in a greenhouse and fields. B. subtilis KB-401 showing inhibitory effect on mycelial growth of various phytopathogenic fungi was formulated for the evaluation. The formulated biofungicide of B. subtilis KB-401 was less effective at 1,000 times dilution rate than that at 250 or 500 times dilution rate. The powdery mildew was successfully controlled by the biofungicide at the early stage of disease development. The field performance of the biofungicde was conducted in Asan and Cheonan city. Three or four consecutive applications of the biofungicide at 500 dilution rate with 10-day intervals resulted in considerable efficacy of disease control as high as 83.3%.

• Journal of Life Science
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• v.21 no.1
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• pp.96-101
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• 2011

S-Adenosyl-L-methionine synthtase (SAM-s) catalyzes the biosynthesis of SAM from ATP and L-methionine. SAM plays important roles in the primary and secondary metabolism of cells. A metK encoding a SAM-s was searched from Streptomyces natalensis producing natamycin, a predominantly a strong antifungal agent, inhibiting the growth of both yeasts and molds and preventing the formation of aflatoxin in filamentous fungi. To obtain the metK of S. natalensis, PCR using primers designed from the two highly conserved regions for metK genes of Streptomyces strains was carried out, and an intact 1.2-kb metK gene of S. natalensis was cloned by genomic Southern hybridization with PCR product as a probe. To identify the function of the cloned metK gene, it was inserted into pSET152ET for its high expression in the Streptomyces strain, and then introduced into S. lividans TK24 as a host by transconjugation using E. coli ET12567(pUZ8002). The high expression of metK in S. lividans TK24 induced actinorhodin production on R5 solid medium, and its amount in R4 liquid medium was 10-fold higher than that by exconjugant including only pSET152ET.