• KSBB Journal
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• v.21 no.5
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• pp.331-335
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• 2006

Suspension cells of Angelica gigas Nakai were cultivated to produce extracellular polysaccharide(ECP) as immunostimulating agents. Effects of environmental conditions such as sucrose and 2,4-dichlorophenoxyacetic acid(2,4-D) concentrations on the growth and production of ECP were studied using suspension cultures of A. gigas Nakai. Final dry cell weight was increased with an increase of initial sucrose concentration from 30 to 60 g/L. The maximum production of ECP(1.2 g/L) was achieved at an initial sucrose concentration of 50 g/L on day 8. High 2,4-D concentration was effective for ECP production but not for cell growth. In addition, various fungal elicitors were investigated for the enhanced production of ECP in A. gigas suspension cultures. Among the tested fungal elicitors, Verticillium dahliae was the most effective for the production of ECP in A. gigas suspension culture.

• The Plant Pathology Journal
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• v.32 no.3
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• pp.273-280
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• 2016

Most biocontrol agents for plant diseases have been isolated from sources such as soils and plants. As an alternative source, we examined the feces of tertiary larvae of the herbivorous rhino beetle, Allomyrina dichotoma for presence of biocontrol-active microbes. The initial screen was performed to detect antifungal activity against two common fungal plant pathogens. The strain with strongest antifungal activity was identified as Bacillus amyloliquefaciens KB3. The inhibitory activity of this strain correlated with lipopeptide productions, including iturin A and surfactin. Production of these surfactants in the KB3 isolate varied with the culture phase and growth medium used. In planta biocontrol activities of cell-free culture filtrates of KB3 were similar to those of the commercial biocontrol agent, B. subtilis QST-713. These results support the presence of microbes with the potential to inhibit fungal growth, such as plant pathogens, in diverse ecological niches.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.217-222
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• 2004

As Agrobacterium tumefaciens, which has long been used to transform plants, is known to transfer T-DNA to budding yeast, Saccharomyces cerevisiae, a variety of fungi were subjected to the A. tumefaciens-mediated transformation to improve their transformation frequency and feasibility. The A. tumefaciens-mediated transformation of chestnut blight fungus, Cryphonectria parasitica, is performed in this study as the first example of transformation of a hardwood fungal pathogen. The transfer of the binary vector pBIN9-Hg, containing the bacterial hygromycin B phosphotransferase gene under the control of the Aspergillus nidulans trpC promoter and terminator, as a selectable marker, led to the selection of more than 1,000 stable, hygromycin B-resistant transformants per 1${\times}$10$\^$6/ conidia of C. parasitica. The putative transformants appeared to be mitotically stable. The transformation efficiency appears to depend on the bacterial strain, age of the bacteria cell culture and ratio of fungal spores to bacterial cells. PCR and Southern blot analysis indicated that the marker gene was inserted at different chromosomal sites. Moreover, three transformants out of ten showed more than two hybridizing bands, suggesting more than two copies of the inserted marker gene are not uncommon.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.11a
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• pp.103-115
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• 2006

$\beta$-Glucan is a glucose polymer that has linkage of $\beta$-(1,3), -(1,4) and -(1,6). As exclusively found in fungal and bacterial cell wall, not in animal, $\beta$-glucans are recognized by innate immune system. Dendritic cells (DC) or macrophages possesses pattern recognition molecule (PRM) for binding $\beta$-glucan as pathogen-associated molecular pattern (PAMP). Recently $\beta$-glucan receptor was cloned from DC and named as dectin-l which belongs to type II C-type lectin family. Human dectin-1 is consisted of 7 exons and 6 introns. The polypeptide of dectin-1 has 247 amino acids and has cytoplasmic, transmembrane, stalk and carbohydrate recognition domains. Dectin-1 could recognize variety of beta-1,3 and/or beta-1,6 glucan linkages, but not alpha-glucans. In our macrophage cell line culture system, dectin-1 mRNA was detected in RA W264.7 cells by reverse transcription-polymerase chain reaction (RT-PCR). Dectin-1 was also detected in the murine organs of spleen, thymus, lung and intestines. Treatment of RA W264.7 cells with $\beta$-glucans of Ganoderma lucidum (GLG) resulted in increased expression of IL-6 and TNF-$\alpha$ in the presence of LPS. However, GLG alone did not increase IL-6 nor TNF-$\alpha$. These results suggest that receptor dectin-1 cooperate with CD14 to activate signal transduction that is very critical in immunoresponse.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.435-441
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• 2009

In the present study, we analyzed the defensin protein deduced from Korean radish (Raphanus sativus L.) seeds.To express the genes in E. coli, we constructed a recombinant expression vector with a defensin gene, named rKRs-AFP gene isolated from Korean radish seeds. Over expressed rKRs-AFP proteins was separated by SDS-PAGE to determine the purity, and protein concentration was determined by the Bradford method. Antifungal activity was assessed by disk assay method against the tested fungi. As a result, when 500 mL of cell culture were disrupted by sonicator, 32.5 mg total proteins were obtained. The purified protein showed a single band on SDS-PAGE with estimated molecular weight about 6 KDa, consistent with the molecular mass calculated from the deduced amino acid sequence. The purified rKRs-AFP protein showed remarkable antifungal activities against several fungi including Aspergillus niger, Botrytis cinerea causing the gray mold disease, and Candida albicans. In field tests using the purified rKRs-AFP protein, the protein showed the reducing activity of disease spot and the mitigating effect of spreading of disease like agrichemicals. The immuno-assay of rKRs-AFP protein showed that the purified protein entirely accumulated at B. cinerea cytoplasm through the hyphal septa shown by fluorescence imaging. There was no fluorescence inside the cell, when the hypha was incubated without the protein. These all results indicate that the recombinant rKRs-AFP proteins can be utilized as a potential antifungal drug to control harmful plant fungal pathogens.

• 한국약용작물학회:학술대회논문집
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• 2006.11a
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• pp.103-115
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• 2006

[ ${\beta}-Glucan$ ] is a glucose polymer that has linkage of ${\beta}-(1,3)$, -(1,4) and -(1,6). As exclusively found in fungal and bacterial cell wall, not in animal, ${\beta}-glucans$ are recognized by innate immune system. Dendritic cells (DC) or macrophages possesses pattern recognition molecule (PRM) for binding ${\beta}-glucans$ as pathogen-associated molecular pattern (PAMP). Recently ${\beta}-glucans$ receptor was cloned from DC and named as dectin-l which belongs to type II C-type lectin family. Human dectin-l is consisted of 7 exons and 6 introns. The polypeptide of dectin-l has 247 amino acids and has cytoplasmic, transmembrane, stalk and carbohydrate recognition domains. Dectin-l could recognize variety of beta-l,3 and/or beta-l,6 glucan linkages, but not alpha-glucans. In our macrophage cell line culture system, dectin-l mRNA was detected in RA W264.7 cells by reverse transcription-polymerase chain reaction (RT-PCR). Dectin-l was also detected in the murine organs of spleen, thymus, lung and intestines. Treatment of RA W264.7 cells with ${\beta}-glucans$ of Ganoderma lucidum (GLG) resulted in increased expression of IL-6 and $TNF-{\alpha}$ in the presence of LPS. However, GLG alone did not increase IL-6 nor $TNF-{\alpha}$ These results suggest that receptor dectin-l cooperate with CD14 to activate signal transduction that is very critical in immunoresponse.

• Korean Journal of Food Science and Technology
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• v.20 no.5
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• pp.724-731
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• 1988

For a study on the production of ${\gamma}-linolenic$ acid(GLA) by microorganisms, fifteen strains of Mucorales obtained from culture stocks and ten isolate strains were compared in their cell growth, lipid content, fatty acid composition and pellet size formed in shake flask culture. Among the fungi examined, the isolated fungus, designated as FB-354, was found to be the most suitable one for the production of GLA mainly due to its high contents of lipid, 29.9% of dry cell weight and GLA, 16.8% of the total fatty acids. The strain FB-354 was tentatively identified as Mucor sp. on the basis of morphological characteristics. Fungal oil produced by Mucor sp. FB-354 was fractionated into 81.1% of neutral lipid, 7.2% of glycolipid, and 11.8% of phospholipid. Although the GLA content in the phospholipid fraction was as high as 21.4%, most of the GLA was found in the neutral lipid fraction.

• Korean Journal of Microbiology
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• v.11 no.3
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• pp.121-128
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• 1973

In order to clarify the best cultural conditions of Rhizopus niveus the effects of aeration, pH and various nutrients, such as different carbon and nitrogen sources, vitamins, and growth substances, on the mycelial growth were studied through liquid culture, and amylase activities of the fungus at different cultural periods were measured. Soluble starch, xylose and galactose are excellent sources of carbon for growth of the fungus. Sorbose and lactose are utilized slightly for growth. peptone, ammonium sulfate and alanine are excellent nitrogen sources for growth, tyrptophane nad potassium nitrate are utilized slightly for growth and sodium nitrite is not utilized. Thiamine nad gibberellin are excellent growth substances for the fungal growth, and biotin, nicotinamide and indole acetic acid (IAA) are also effective. Rhizopus niveus grows better at rotatory culture than at stationary culture and earlier growth of the fungus increases remarkably at rotatory culture. Optimum pH than at pH3. Growth increases linerly with an increase of soluble starch content up to 100g per liter medium, but 5 grams of ammonium sulfate per liter is the optimum nitrogen concentration for growth, if Pfeffer's medium is employed. Amylase activities of Rhizopus at different cultural periods showed that the maximum amylase production takes place after the cell population has reached its peak in the culture. Dextrinogenic amylase production has reached maximum at stationary phase, and maximum saccharogenic maylase production takes place in the pahse of negative gorwth acceleration.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.469-472
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• 2002

Solid state fermentation was performed for the production of entomopathogenic fungus Metarhizium anisopliae HY-2 using wheat bran media containing rice bran. Fungal growth in a solid state fermentation system was estimated by viable cell count, spore count, and mycelial biomass. It was used chemical method measuring N-acetyl-glucosamine (chitin) content for estimating of mycelial biomass. In static flask culture, viable cell reached 2.40 ${\times}$ $10^8$ cfu/g at 23 days of culture at $27^{\circ}C$ and then mycelial biomass was 41.59 mg/g. Specific growth rate(${\mu}$ max) was 0.0418 $h^{-1}$ between 3 and 9 days when estimated by viable cell count and was 0.00976 $h^{-1}$ between 9 and 17 days when N-acetylglucosamine content was measured. Viable cells reached 1.12 ${\times}$ $10^8$ cfu/g in polypropylene-bag at 28 days of culture at $27^{\circ}C$. Formulated microbial pesticide containing M. anisopliae HY-2 were tested their bio-activity against Chestnut Brown Chafer (Adoretus tenuimaculatus). The protection rate of the liquid culture showed 13 ${\sim}$ 26 % with 1st to 3rd instar, and spore suspension of M. anisopliae HY-2 showed 56 ${\sim}$ 64%. Conidia produced by large scale solid-state fermentation showed 20 ${\sim}$ 27 % activity 60 ${\sim}$ 64 % with M. anisopliae HY-2.

• Journal of fish pathology
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• v.4 no.2
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• pp.95-100
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• 1991

Saprolegnia diclina, which was the pathogen causing death in snake fishes(Channa argus) at culture farm, was investigated using scanning electron microscope. It was found that Saprolegnia diclina infection caused snake fishes to fail gas change in the gills. Cell lysis as well as edematous disease and hyperplasia as a result of Saprolegnea diclina attachment on the surface of gills were observed. The granules, the mean diameters of which ranged from 6 to $7\;{\mu}m$, attaching on the surface of gills were found to be secondary zoospores of Saprolegnia diclina. The failures of gas exchange in the gill cells and circulation as a result of the osmotic dilution of the blood were supposed to be the main cause of death.