• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.185-194
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• 2006

A fungal strain of Trichoderma having strong chitinolytic activity was isolated from field soil enriched with crabshell for several years. Based on 5.8S rRNA, partial 18S, 28S rRNA genes, ITS1, ITS2 sequence analysis and morphological characteristics, the fungus was identified as Trichoderma asperellum and named as Trichoderma asperellum T-5 (TaT-5). The fungus released lytic enzymes such as chitinase and ${\beta}$-1, 3-glucanse, and produced six antifungal substances in chitin broth medium. To demonstrate the protective effect of TaT-5 against damping-off in cucumber plant caused by Rhizoctonia solani, TaT-5 culture broth (TA), chitin medium (CM) and distilled water (DW) were applied to each pot at 10 days after sowing, respectively. Then, the homogenized hyphae of R. solani were infected to each pot at 1 week after TaT-5 inoculation. During experimental period, fresh weight of shoot and root in cucumber plant more increased at TA treatment compared to other treatments. PR-proteins (${\beta}$-1, 3-glucanase and chitinase) activities in cucumber leaves markedly increased at CM and DW treatments, but the activity slightly increased and then decreased at TA treatment at 3 days after infection of R. solani. The activity of PR-proteins activities in cucumber roots at all treatments decreased with time where the degree of decrement was more alleviated at TA treatment than CM and DW. These results suggest that the lytic enzymes (chitinase and ${\beta}$-1, 3-glucanse) and antifungal substances produced by TaT-5 can reduce the pathogenic attack by R. solani in cucumber plants.

• The Korean Journal of Mycology
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• v.43 no.3
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• pp.149-157
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• 2015

We examined taxonomic characteristics and safety of eight Nuruk molds that are widely used for making soybean paste, soy sauce and alcoholic beverages in Korea. HK1 from Hakyeong Fermentation Co., SW101 from Suwon Fermentation Co., CF1001, CF1002, CF1003 from Chungmoo Fermaentation Co. and KACC 93210 are yellow-Nuruk molds, and SW201 from Suwon Fermentation Co. and CF1005 from Chungmoo Fermentation Co. are white-Nuruk molds. Six strains of yellow-Nuruk molds were identified as Aspergillus oryzae. HK1, SW101, CF1001 and CF1003 of yellow-Nuruk molds have middle length of stipes ($711{\sim}1,121{\mu}m$), and CF1003 (for sake) produced less conidia and more hyphae than HK1, SW101 and CF1001 (for soybean paste). CF 1002 used for soy sauce has shorter stipes ($543{\mu}m$) and is clustered into IBLB-group based on omtA gene analysis although the other yellow-Nuruk molds are clustered into ICAo group. KACC 93210 isolated from traditional Korean Meju has very short stipes (average $270{\mu}m$), and showed velvety colonies although the others showed floccose colonies. The strain has different DNA sequences of omtA gene from other strains in NCBI GenBank as well as strains used in Korea, suggesting that it is unique from other strains published. SW201 and CF1005 of white-Nuruk molds were identified as Aspergillus luchuensis or A. luchuensis mut. Kawachii that is known as safe, non-toxigenic fungus. The six strains of yellow-Nuruk molds did not produce mycotoxins including aflatoxin, cyclopiazonic acid, and sterigmatocystin. Therefore, eight strains of Nuruk molds used for making soy sauce, soybean paste and alcoholic beverages in Korea were proved to be safe in this study.

• Journal of Mushroom
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• v.12 no.3
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• pp.209-215
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• 2014

Changes in physical and chemical properties of oak sawdust were investigated by depth and time for 46 days during the fermentation process of 33 tons of the sawdust for oak mushroom cultivation. The degrees of change in the properties of the sawdust differed depending on the depth and fermentation period. Most of the physical-chemical properties except temperature and pH gradually changed during the fermentation. The temperature change was highly sensitive to the environment at the surface sawdust to 20 cm depth, while it gradually increased to the maximum $58.9^{\circ}C$ at 40~100 cm depths in 12 days and slowly to the maximum at 150 cm depth in 24 days. The moisture content of the sawdust decreased gradually from 31% to 26.5~28.0% in 24 days. Of the chemical properties during the fermentation, pH generally rose from 5.2 to 5.6, but it decreased to 4.4~4.7 at 150 cm depth in 16 days. While the carbon content of the sawdust was 68~70% without significant change, nitrogen content increased from 0.22% to 0.25% and thus C/N ratio gradually lowered from 320 to 280. P content in the sawdust gradually increased from 0.005% to 0.022% for 46 days. Osmotic concentration of the hot water extract of the sawdust varied 41.5~44.2 mmol/kg without significant change by the depth and time. The starch particles within initial ray parenchyma cells of sawdust decreased and fungal hyphae formed on the surface of the sawdust granules and within xylem vessel cells in 35 days. The effect of the sawdust fermentation on oak mushroom cultivation needs continued research.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.229-237
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• 1987

In order to study the biological control of soil-borne disease of sesame, antagonistic isolates of Trichoderma , Bacillus sand streptomyces to Fusarium oxysporum and Rhizoctonia solani were isolated from the rhizosphere soils of sesame plants and some other habitats. Out of the isolates of microorganisms collected a strain of Trichoderma viride was selected as a biological control agent for the study and its effect on the control of damping-off and the seedling growth of sesame was investigated. The results obtained are as follows: 26 percents of Bacillus spp. isolated from the rhizosphere soil of sesame plants showed antagonism to two pathogenic fungi. Important species were B. Subtilis and B. polymyxa. Streptomyces species isolated from the rhizosphere soils of sesame lysed the cell wall of hyphae and conidia of F. oxysporum and reduced conspicuously the formation of macroconidia and chlamydospores of the fungus. 84 percents of Trichoderma spp. isolated from the rhizosphere soil of sesame plants were antagonistic to F. oxysporum and 60 percents of the isolates were antagonistic to both F. oxysporum and R. solani. Trichoderma viride TV-192 selected from antagonistic isolates of Trichoderma spp. was highly antagonistic to F. oxysporum and soil treatment with the isolate reduced notably damping-off of sesame. T. viride TV-192 showed better growth in crushed rice straw, barley straw and sawdust media than F. oxysporum. Sawdust was selective for the growth of T. viride. Supplementation of wheat bran and mixtures of wheat bran and sawdust inoculated with T. viride TV-192 in the soil reduced remarkably damping-off of sesame by F. oxysporum but high density of the fungus TV-192 caused the inhibition of seed germination and seedling growth of sesame. Inhibitory effects of Trichoderma species on seed germination and seedling growth of sesame were different according to the isolates of the fungus. Normal sesame seedlings on the bed treated with the fungus showed better growth than not treated seedlings.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.201-209
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• 2014

This study was carried out in order to develop a biological control of anthracnose of red pepper caused by fungal pathogens. In particular, this study focuses on the Colletotrichum species, which includes important fungal pathogens causing a great deal of damage to red pepper. Antagonistic bacteria were isolated from the soil of pepper fields, which were then tested for biocontrol activity against the Colletotrichum gloeosporioides anthracnose pathogen of pepper. Based on the 16S rRNA sequence analysis, the isolated bacterial strain CS-52 was identical to Bacillus sp. The culture broth of Bacillus sp. CS-52 had antifungal activity toward the hyphae and spores of C. gloeosporioides. Moreover, the substances with antifungal activity were optimized when Bacillus sp. CS-52 was grown aerobically in a medium composed of 0.5% glucose, 0.7% $K_2HPO_4$, 0.2% $KH_2PO_4$, 0.3% $NH_4NO_3$, 0.01% $MnSO_4{\cdot}7H_2O$, and 0.15% yeast extract at $30^{\circ}C$. The inhibition of spore formation resulting from cellulase, siderophores, and indole-3-acetic acid (IAA), were produced at 24 h, 48 h, and 72 h, respectively. Bacillus sp. CS-52 also exhibited its potent fungicidal activity against anthracnose in an in vivo test, at a level of 70% when compared to chemical fungicides. These results identified substances with antifungal activity produced by Bacillus sp. CS-52 for the biological control of major plant pathogens in red pepper. Further studies will investigate the synergistic effect promoting better growth and antifungal activity by the formulation of substances with antifungal activity.

• Research in Plant Disease
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• v.12 no.1
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• pp.15-19
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• 2006

This study was carried out to know pathogenicity of the pathogen isolated in several location of Korea and penetration mechanism of the Pseudocercospora vitis ($(L\acute{e}v)$.) Speg. Inoculation tests at room temperature were performed on both sides of leaves with different isolates of the fungus. The typical symptoms appeared on the abaxial leaf surface, but no symptom was observed on the adaxial leaf surface with all isolates. The average incubation period was nine days, since all symptoms appeared from 8 to 10 days after inoculation. In order to know the mechanism of invasion of P. vitis to grapevine, the behavior of penetration hyphae through stomata were compared in two cultivars having different level of resistance. In order to know the mechanism of resistance of grape vine to P.vitis, two cultivars having different level of resistance were compared by counting the numbers and measuring size of the stomata per leaf. In a susceptible cultivar Campbell Early, the number of stomata was more than that of a resistance cultivar 'Kyoho'. In a susceptible cultivar 'Campbell Early', the fungus entered readily into stomata after inoculation. However, in a resistant cultivar 'Kyoho', the fungus seemed to pass over or surrounded only the guard cells. In comparison of height of guard cells of stomata between the two cultivars, significant differences were observed by scanning electron microscopy and light microscopy. The height of guard cells of 'Campbell Early' showed a little higher than those of 'Kyoho' known to be resistant to the fungus.

• Korean Journal of Organic Agriculture
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• v.13 no.4
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• pp.401-412
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• 2005

This study was conducted to examine the effects of dietary Mogchotan(the mixture of charcoal and pyroligneous acid, 80:20, w/w) supplementation on fattening performance, fatty acid composition and the physico-chemical characteristics of meat in pigs. The present study was also stressed to investigate the possibility of industrial utilization of charcoal and pyroligneous acid as a livestock feed additive. Weight gain and feed conversion in pigs fed the Mogchotan supplemented diet were higher than those of the control group. In fatty acids composition, palmitic acid(C16:0) contents of Mogchotan treatment groups were lower than that of control group. However, Mogchotan supplementation increased C16:1, C18:0, C18:1, C18:2 and C18:3 contents when compared with control group pigs. Also, Mogchotan supplementation groups decreased saturated fatty acids level than control group. On the other hand, Mogchotan supplementation showed higher unsaturated fatty acids value, especially polyunsaturated fatty acids value compared to control group. The carcass pH of pigs fed the Mogchotan tended to be higher than control, but was not significantly different. The water holding capacity was significantly higher in pigs fed the 3.0% Mogchotan-supplemented diet than those of other treatment groups(p<0.05). Altogether, it has been suggested that dietary $1{\sim}3%$ of Mogchotan supplementation improved the fattening performance and meat quality in pigs.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.170-176
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• 2008

This study was carried out to improve density of arbuscular mycorrhizal fungi (AMF) propagule and physiochemical properties of soil by planting crops at the preplanning field for ginseng cultivation. Winter crops, such as barley and rye and summer crops, such as sudangrass and soybean were cultivated in combination to improve AMF propagation and soil aggregation at the fields. Yield of harvested crops by plating with winter or/and summer crops was $3,045kg\;10a^{-1}$ of the only rye cultivation, $2,757kg\;10a^{-1}$ of sudangrass cultivation in combination with rye growing (rye/sudangrass) and $1,628kg\;10a^{-1}$ of soybean cultivation in combination with barley growing (barley/soybean), respectively. Soil aggregation rate was improved by cultivation with barley (45.7%) and with rye/sudangrass (45.1%), respectively. The density of AMF spores in soil was increased slowly by cultivating with winter crops. In summer crops cultivation system, density of AMF spores at sudangrass cultivated field was $64.0spores\;g^{-1}$ dried soil and it was higher than that at soybean cultivated field. External hyphae length (EHL) was $1.5{\sim}2.0m\;g^{-1}$ air-dried soil at winter crops cultivated field. However, in summer crops cultivation systems, EHL was $2.6{\sim}2.9m\;g^{-1}$ airdried soil at sudangrass cultivated field and was $1.7{\sim}2.2m\;g^{-1}$ air-dried soil at soybean cultivated filed, showing these were higher than those in non-cultivated field (control). Glomalin content of soil cultivated with crops was higher than that of control soil. Especially, the highest glomalin content was shown to $1.7m\;g^{-1}$ air-dried soil in the barley/soybean cultivation systems. These results suggested that the most effective soil management to improve AMF propagule density and soil physical properties by planting crops system was cultivating sudangrass followed by barley at the preplanning fields for ginseng cultivation.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.50-61
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• 1994

From soil samples, 380 antagonistic microorgnisms were isolated. Among the isolates, 42 strains had mycelia growing inhibition ability against Fusariun solani, ginseng root rot causing pathogen. Isolates CHA 1 and S-PFHR 6 were proposed as antagonists for this study and they were identified as Promicromonospora sp. and Pseudomonas pseudoalcaligenes respectively. As an antagonism against hyphae of F. solani in dual culture test, CHA 1 and S-PFHR 6 inhibited linear growing, caused abnormal branching, and the membrane projection which formed by cell wall destruction. The secondary metabolites contained in the culture filtrates which prepared from PD broth and Nutrient broth inhibited the spore germination to 14.3%. The culture filtrate of S-PFHR 6 which prepared by a little amount of soil extract addition to nutrient rich medium had more strongly. inhibited the spore germination and spore germination decreased to less than 4.0% in it. The soil used in this study had fungistasis and the germination rate of macroconidia and chlamydospore of F.solani was 19.4% and 17.7% respectively. The steam sterilized soil lost fungistasis and germination rate of conidia increased to more than 97.9%. The soils amended with the propagule of CHA 1 and S-PFHR 6 increased fungistasis and the germination rate of macroconidia decreased to 14.7% and 11.7% respectively in each treatments. But the soil ammended with glucose and asparagine annulled fungistatic ability and the germination rate of macroconidia increased to more than 48.0%. As an antagonistic activity of the secondary metabolites of two antagonistic isolates in soil, the germination rate of macroconidia of F. solani was 9.3% in the soil amended with the culture filtrate of CHA 1 but the culture filtrate of S-PFHR 6 had no such activity. In the soil which treated with antagonist propagule or culture filtrate, the chlamydospore germination rate was lower than that in natural soil. The addition of glucose and asparagine to antagonist propagule treated soil did not enhanced the chlamydospore germination.

• Journal of Yeungnam Medical Science
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• v.6 no.1
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• pp.47-57
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• 1989

T. verrucosum infection has been reported for the first time in 1986 in Korea and has been increasing progressively. To evaluate the progress of clinical and histopathological change of dermatophytosis caused by T. verrucosum, inoculation study, using T. verrucosum isolated from infected human(human strain) and from infected cattle(cattle strain), was done in 24 male albino Hartley guinea pig. Their clinical and histopathological changes were evaluated. In addition, comparison for the growth rate between human strain and cattle strain on Sabouraud's glucose agar was made. The results were as follows: 1. Growth rate on Sabouraud's glucose agar : Cattle strain showed significantly more rapid growth rate than human strain on Sabouraud's glucose rate at $25^{\circ}C$ and $37^{\circ}C$. And cattle strain showed more rapid growth rate at $37^{\circ}C$ than $25^{\circ}C$. But human strain showed no significant difference of growth rate at both temperature. 2. Clinical findings: Initial erythema, scale and crust were developed about 8th after inoculation. All three findings reached maximum severity about 12th to 16th day and disappeared about 30th to 34th day after inoculation. There was no significant difference in progress of erythema, scale and crust between cattle strain and human strain. 3. Histopathological findings: Although mild acanthosis was noticed on the 3rd day after inoculation, the other findings including parakeratosis, intraepidermal abscess, spongiosis and vascular change, cellular infiltration were found on 9th day after inoculation. They reached maximum severity on the 12th day and lasted to the 25th day after inoculation. After that, all three findings were decreased gradually between 29th day and 33th day. On the PAS stainings, hyphae and spores were found on the 6th day and disappeared on the 21th day after inoculation. 4. In trichophytin skin test, all of the 24 guinea pigs became positive within average $9.83{\pm}1.17$ lays. These findings suggested that dermatophytosis caused by T. verrucosum induced rapid cell mediated immunity and contributed to rapid resolution of the lesion.