• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.13-13
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• 2014

Species belonging to the genus Fusarium are widely distributed and cause diseases in many plants. Isolation of fungal strains from air or cereals is necessary for disease forecasting, disease diagnosis, and population genetics [1]. Previously we showed that Fusarium species are resistant to toxoflavin produced by the bacterial rice pathogen Burkholderia glumae while other fungal genera are sensitive to the toxin, resulting in the development of a selective medium for Fusarium species using toxoflavin [2]. In this study, we have tried to elucidate the resistant mechanism of F. graminearum against toxoflavin and interaction between the two pathogens in nature. To test whether B. glumae affects the development of F. graminearum, the wild-type F. graminearum strains were incubated with either the bacterial strain or supernatant of the bacterial culture. Both conditions increased the conidial production five times more than when the fungus was incubated alone. While co-incubation resulted in dramatic increase of conidial production, conidia germination delayed by either the bacterial strain or supernatant. These results suggest that certain factors produced by B. glumae induce conidial production and delay conidial germination in F. graminearum. To identify genes related to toxoflavin resistance in F. graminearum, we screened the transcriptional factor mutant library previously generated in F. graminearum [3] and identified one mutant that is sensitive to toxoflavin. We analyzed transcriptomes of the wild-type strain and the mutant strain under either absence or presence of toxoflavin through RNAseq. Expression level of total genes of 13,820 was measured by reads per kilobase per million mapped reads (RPKM). Under the criteria with more than two-fold changes, 1,440 genes were upregulated and 1,267 genes were down-regulated in wild-type strain than mutant strain in response to toxoflavin treatment. A comparison of gene expression profiling between the wild type and mutant through gene ontology analysis showed that genes related to metabolic process and oxidation-reduction process were highly enriched in the mutant strain. The data analyses will focus on elucidating the resistance mechanism of F. graminearum against toxoflavin and the interaction between the two pathogens in rice. Further evolutionary history will be traced through figuring out the gene function in populations and in other filamentous fungi.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.535-540
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• 1990

Bacitlus sphaericus ts-Dl290 was characterized comparatively with the wild type strain 1593 by themeasurements of the biosynthesis of total DNA, RNA and protein on the temperature-shift culturesat permissive temperature of $30^{\circ}C$ and at nonpermissive temperature of $42^{\circ}C$. The growth patterns of the wild type strain and ts-Dl290 were similar at $30^{\circ}C$, but at 4Z C the mutant almost did not grow (temperature-sensitivity). When the growth temperatures of both stains were shifted-up from $30^{\circ}C$ to $42^{\circ}C$ after a 4 hour culture, their growths were normal, but when shifted-down from $42^{\circ}C$ to $30^{\circ}C$ after a 4 h culture, the mutant did not grow. When shifted up from $30^{\circ}C$ to $42^{\circ}C$ after a 4 hculture, the DNA syntheses of the two strains were at a normal rate for 1 h, but after 1 h the biosynthesesdecreased. The rate of DNA synthesis of the wild type strain at the nonpermissive temperature was about 93%, and that of the mutant was about 50% of the ratio of the wild type strain, and the RNA synthesis of the wild type strain was maintained for 3 h, and that of the mutant for 2 h. Thereafter the RNA synthesis decreased, and the synthesis of proteins in the both strains were similarlykept high for 8 h. The reversibility of the DNA synthesis of the mutant at $42^{\circ}C$ was lessened whenthe culture times were increased.re times were increased.

• Mycobiology
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• v.41 no.3
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• pp.139-144
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• 2013

Makgeolli is a traditional cloudy-white Korean rice wine with an alcohol content of 6~7%. The present study investigated the morphological characteristics, carbon-utilizing ability, fatty acid composition, alcohol resistance, glucose tolerance, and flocculence of Saccharomyces cerevisiae Y98-5 and Pichia anomala Y197-13, non-S. cerevisiae isolated from Nuruk, which is used in brewing Makgeolli. Similar morphological characteristics were observed for both isolated wild yeast strains; and the carbon source assimilation of Y197-13 differed from that of other P. anomala strains. Strain Y197-13 was negative for D-trehalose, mannitol, arbutin, I-erythritol, and succinic acid. The major cellular fatty acids of strain Y197-13 included C18:2n6c (33.94%), C18:1n9c (26.97%) and C16:0 (20.57%). Strain Y197-13 was Crabtree-negative, with 60% cell viability at 12% (v/v) ethanol. The flocculation level of strain Y197-13 was 8.38%, resulting in its classification as a non-flocculent yeast.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.229-235
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• 2020

The goal of this study was to isolate and identify the wild yeast strains in intestine of Othius punctulatus collected in Cheongju-si, Chungcheongbuk-do, Korea and characterize their unrecored yeast strains. We isolated 16 wild yeast strains from 5 intestine samples from Othius punctulatus. The 16 wild yeast strains were included three strains in the genus Aureobasidium, four strains in the genus Cystofilobasidium, one strain in the genus Mrakia, three strains in the genus Naganishia, two strains in the genus Saitozyma, two strains in the genus Sampaiozyma and one strain in the genus Scheffersomyces. Among them Cystofilobasidium capitatum YP53, Cystofilobasidium capitatum YP71, Cystofilobasidium macerans YS620, Cystofilobasidium macerans YS622, Mrakia aquatica YP158 and Scheffersomyces stipitis YI5 were recorded for the first time in Korea. The microbiological characteristics and carbon assimilation of these previously unrecorded yeasts were investigated. Almost all of them were oval-shaped. And, glycerol, L-arabinose, xylitol, and inositol are not utilized.

• Preventive Nutrition and Food Science
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• v.2 no.2
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• pp.155-161
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• 1997

The mutagenic and antimutagenic activities of juices from 20 common edible wild herbs found in Korea were investigated using the spore-rec assay and Ames test. The juices of Hemerocallis fulva and Capsella bursapastoris exhibited a little induction or inhibition of mutagenesis in the presence of selected metal ions, but juices of most edible wild herbs did not affect on the mutagenesis in the spore-rec assay. In the other hand, all of the juices strongly inhibited the mutagenesis induced by benzo[a]pyrene, 2-amino-fluorene, and 3-amino-1,4-dimethyl-5H-pyridol tested on Salmonella typhimurium TA98 or TA100 in the presence of S-9 mix. The antimutagenic effects increased as the concentration of the mutagens increase. The results suggest that concentration of samples or types of various mutagen interact to affect the antimutagenic potential of the juices in the TA98 and TA100 strain.

• Journal of the Korean Applied Science and Technology
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• v.9 no.1
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• pp.73-79
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• 1992

To study effects of wild garlic on components of lipid and protein, blood glucose level, and cholinesterase activity in rat's serum, Sprague-Dawley strain of 40 male rats are divided into 5 groups which are Normal, Control, A, B, and C group. Normal group is fed only Basal diet, and Control group is fed Basal diet and 0.5ml/day of 2.5% cholesterol solution, In addition to a diet of control group, A group is fed 25% wild garlic flour, B group 0.5ml/2day of concentratded wild garlic juice, C group 0.5ml/2day of concentrated ethanol extract of wild garlic, After 8 weesk the rats were fasted for 12 hours, and then decapitated to collect blood. The results of analysis of the rat's serum were summarized as follows, 1. Wild garlic diet, specially ethanol extract has an influence on decreasing the level of total cholesterol and blood glucose in rat's serum, 2. HDL-cholesterol and phospholipid content of rat's serum are increased by wild garlic diet. Therefore I think that wild garlic is good food for preventing development of atherosclerosis and diabetes.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.452-460
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• 2016

Acid stress can affect the viability of probiotics, especially Bifidobacterium. This study aimed to improve the acid tolerance of Bifidobacterium longum BBMN68 using adaptive evolution. The stress response, and genomic differences of the parental strain and the variant strain were compared by acid stress. The highest acid-resistant mutant strain (BBMN68m) was isolated from more than 100 asexual lines, which were adaptive to the acid stress for 10^th, 20^th, 30^th, 40^th, and 50^th repeats, respectively. The variant strain showed a significant increase in acid tolerance under conditions of pH 2.5 for 2 h (from 7.92 to 4.44 log CFU/ml) compared with the wild-type strain (WT, from 7.87 to 0 log CFU/ml). The surface of the variant strain was also smoother. Comparative whole-genome analysis showed that the galactosyl transferase D gene (cpsD, bbmn68_1012), a key gene involved in exopolysaccharide (EPS) synthesis, was altered by two nucleotides in the mutant, causing alteration in amino acids, pI (from 8.94 to 9.19), and predicted protein structure. Meanwhile, cpsD expression and EPS production were also reduced in the variant strain (p < 0.05) compared with WT, and the exogenous WT-EPS in the variant strain reduced its acid-resistant ability. These results suggested EPS was related to acid responses of BBMN68.

• 한국균학회소식:학술대회논문집
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• 2009.10a
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• pp.3-13
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• 2009

90 wild Agaricus strains from China, including 44 Agaricus bisporus strains identified preliminarily by isozyme electrophoresis, were studied by the techniques of SRAP and ISSR. 18 special SRAP bands and 12 special ISSR bands were analyzed, the strains were clustered and a demdrogram was obtained. The results showed that the strains were divided into 2 groups, wild A. bisporus group and the other Agaricus group. It is similar to the result of isozyme electrophoresis. 41 wild A. bisporus strains from Sichuan and Tibet were divided into 4 groups based on their growing places, suggesting the regionally difference of the strains to be quite obvious. Some white wild A. bisporus strains from Xinjiang and Tibet had special patterns, resulting in lower coefficient values with other wild A. bisporus strains. The biological characteristics of three wild A. bisporus strains were analyzed, and the results showed: 1. The wild strains grew slowly on PDA medium with weak appressed mycelia, and grew normally in kernel or fermented cottonseed shell substrate. 2. They grew faster than control strain As2796 under lower temperature of $16^{\circ}C$, and higher temperature of $32^{\circ}C$, with optimum growing temperature of $20-24^{\circ}C$, which was $4^{\circ}C$ lower than that of control strain. 3. In the cultivation with manure compost via twice fermentation, the mycelia grew normally in compost and quite slowly in casing soil, and the fruitbodies occurred less and late with easily opening and low production. 4. The fruitbody was off-white with flat and scaled cap, long stipe and dark gill. The bisporus basidia occupied 70-80% and trisporus basidia 20-30% of the total basidia. 5. Heterokaryotic monospore isolates could fruit in cultivation, and the homokaryotic isolates could cross with those derived from overseas wild A.bisporus strains. 6. The electrophoresis phenotype of isozymes such as esterase etc. belonged to high production type (H type). 7. The RAPD patterns made much difference from those of high production, good quality or hybrid strains, which indicated that the wild strains produce a new kind of RAPD type.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.147-152
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• 1991

In order to study effect of the phage ${\phi}$ FSV on the growth of lactic acid bacteria, Lactobacillus casei YIT 9018(wild type strain with prophage) or L. casei HYM 1213 (prophage cured strain) was infected with various concentrations of phage ${\phi}$ FSV (called Lac S21) or wild type virulent phage (called Lac J-1). When L. casei YIT 9018 was infected with Lac S21 under the concentration of $6.0{\times}10^6$ pfu/ml, the growth and lactic acid production of the strain were normal and the number of phages decreased. But L. casei HYM 1213 was susceptible to Lac S21. Regardless of the concentration of the phage infection, the number of phages increased rapidly into $10^9$ to $10^{10}$ pfu/ml at 2 day cultures and was maintained $10^7$ to $10^9$pfu/ml phage until 6 day cultures. The lactic acid production of L. casei HYM 1213 infected with Lac S21 was abnormal. Therefore, phage ${\phi}$ FSV had an evil effect on growth of L. casei HYM 1213, but not L. casei YIT 9018. On the other hand Lac J-1 caused abnormal fermentation to either L. casei YIT 9018 or L. casei HYM 1213.

• Journal of Mushroom
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• v.6 no.3_4
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• pp.115-120
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• 2008

A new commercial strain 'Garlmoe' was developed by crossing monokaryons from selected wild strains. The optimal temperature of mycelial growth was $25^{\circ}C$ but it needed to adjust to $16{\sim}18^{\circ}C$ when incubated at the bottle cultivation. The optimal temperatures of fruiting body initiation and development were almost same to others like as $14^{\circ}C$ and $7{\sim}10^{\circ}C$, respectively. The color of 'Garlmoe' was typical to wild winter mushroom, that is, pileus was brown and lower part of stipe was dark brown. The surface on pileus of 'Garlmoe' was sticky 'Garlmoe' was a good commercial strain with high quality and high productivity characterized as quite even budding habit, straight and strong stipes and convex type pilei. The taste of this variety was very excellent because of better chewing feeling than white ones.