• Computational Structural Engineering
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• v.8 no.4
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• pp.75-85
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• 1995

The purpose of the present study is to develop a computer program which can be used to analyze prestressed concrete structures containing either bonded or unbonded tendons. To accomplish this, first, the concrete, nonprestressed, and prestressed steels are modeled with cyclic constitutive laws to take into account the various loading effects. Then, the hybrid-type element method is derived to improve the computations capability of stresses and strains, especially for the unbonded tendon. Since it allows one to determine the cross-sectional deformations in an element without any assumptions for its deformed shape, the element length can be much longer than that of the conventional finite element method. In order to achieve such a long element, various integral schemes are examined to implement them into the program. Then, the computational method for prestressing effects is developed consistently with the analytical method for the structure. Finally, analytical studies for actual tests were carried out to verify the program developed in this study.

• Journal of Mushroom
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• v.18 no.3
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• pp.214-220
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• 2020

We undertook a breeding program to produce a white button mushroom cultivar with high temperature tolerance in preparation for climate change. The results were as follows. The strains KMCC00540, KMCC00591, and KMCC00643 were selected, and homokaryons were selected and hybrids were identified with ISSR and SSR markers, respectively. The selected hybrids were cultivated in three repetitions at a temperature of 20-25 ℃ and a humidity of 80% or higher. The variation in agricultural traits and fruiting body characteristics was least in the Abs4-2016-121 strain. This line is a hybrid of KMCC00591 and KMCC00875, and field experiments at Gyeongju and Buyeo farms found that the Abs4-2016-121 line has high fruiting body with hardness and delayed opening of pileus at high temperatures, so it was bred as a high-temperature cultivar named 'Hadam'.

• The Korean Journal of Mycology
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• v.37 no.1
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• pp.114-116
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• 2009

In this study, we selected suitable broth media for mass production of Phytophthora capsici oospore, investigated oospore germination and secured $F_1$ progeny. Carrot broth and V8C broth were determined most effective for oospore formation by calculating and comparing oospore concentration produced from 8 different liquid media. Eleven strains were selected from P. capsici (CapA)/P. tropicalis (CapB) and 9 crosses were formed. Oospore progeny were produced, isolated and germinated from A1 and A2 combinations of P. capsici (CapA) with P tropicalis (CapB). This resulted in a total number of 129 $F_1$ isolates of P. capsici/P. tropicalis with a 0.64-4.0% (mean 1.85%) oospore germination.

• Mycobiology
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• v.50 no.4
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• pp.254-257
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• 2022

Wolfiporia cocos is a wood-decay brown rot fungus belonging to the family Polyporaceae. While the fungus grows, the sclerotium body of the strain, dubbed Bokryeong in Korean, is formed around the roots of conifer trees. The dried sclerotium has been widely used as a key component of many medicinal recipes in East Asia. Wolfiporia cocos strain KMCC03342 is the reference strain registered and maintained by the Korea Seed and Variety Service for commercial uses. Here, we present the first draft genome sequence of W. cocos KMCC03342 using a hybrid assembly technique combining both short- and long-read sequences. The genome has a total length of 55.5 Mb comprised of 343 contigs with N50 of 332 kb and 95.8% BUSCO completeness. The GC ratio was 52.2%. We predicted 14,296 protein-coding gene models based on ab initio gene prediction and evidence-based annotation procedure using RNAseq data. The annotated genome was predicted to have 19 terpene biosynthesis gene clusters, which was the same number as the previously sequenced W. cocos strain MD-104 genome but higher than Chinese W. cocos strains. The genome sequence and the predicted gene clusters allow us to study biosynthetic pathways for the active ingredients of W. cocos.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.315-321
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• 1999

This study has been performed to deveope a yeast strain having high ${\alpha}$-amylase production ability using nuclear transfer method. Hybrids formed between the strains of Saccharomyces fiburigera KCTC 7393 and Saccharomyces cerevisiae KCTC 7049 (tyr-, ura-)were obtained by nuclear transfer technique. Nuclei isolated from the wild type S. fiburigera strain were transfered into auxotrophic mutants S. cerevisiae and selected the hybrids showing an increased starch degrading capability were selected (MN-16). This transformant grew best and produced maximal ${\alpha}$-amylase activity on the medium containing 2% (V/V) soluble starch. ${\alpha}$-Amylase from MN-16 was purified electrophoretically homogenety and its properties were investigated. The enzyme was purified about 10.6 fold with an overall yield 9.7% from the culture medium by ammonium sulfate fractionation. DEAE-Sephacel column chromatography, and Sephacryl S-200 column chromatography. The purified enzyme showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight of the ${\alpha}$-amylase was estimated to be 53,000 daltons by SDS-PAGE and by gel permeation chromatography on Sephacryl S-200. The purified enzyme showed the maximum activity at pH 5.5 and 40${\circ}C$. The km value for soluble starch was 2.5㎎/㎖. The enzyme activity increased in the presence of $Ca^{2+}, Co^{2+}, EDTA, Mg^{2+}, Mn^{2+}, Zn^{2+}$, but inhibited by $Cu^{2+}, Fe^{2+}$, and $Ni^{2+}$

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.371-376
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• 1992

Plasmid pSL4 of plasmid pKM 101 mutant have high protection effects and mutagenecity for UV and methyl methanesulfonate, The mucA gene and a pan of mucE gene of pKM 101 and pSL4 were sucloned onto lacZ' fusion vector pMC874 and the hybrid plasmids pBH31 and pBH30 were selected. These plsmids were intrduced into $recA^{+}lexA^{-}$, $recA^{-}와lexA^{+}$ strains and determined the activity of $\beta$-galactosidase for UV. In $recA^{+}lexA^{+}$ strain.$\beta$-galactosidase activity of pBH30 included mue region of pSL4 was higher thall pBH31 inclued muc region of pKM 10 I and the tf-galactosidase of two plasmids was not induced in reeA and leeA mutants with or without UV illumination. Without UV illumination. the .$\beta$-galactosidasc of pBH30 was expressed a little higher level than that of pBH3L We suggest that the functional difference of pKM 10l and pSL4 are due to the variety of mue regulatory region. Also. a plasmid pBH 100 earring umuC' -lacZ' gene fusion was constructed in vitro to study the regulation of the umu operon. It was shown that the umu operon is induced by UV and is regulated by the reeA and lexA genes.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.142-149
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• 1988

This experiment was carried out to obtain a hybrid with potent ethanol fermenting ability, by means of protoplast fusion between a thermophilic strain (D-71) of Saccharomyces cerevisiae and an osmotolerant strain (SR-S) of Zygosaccharomyces rouxii. The conditions for formation of protoplasts from both strains and for their fusion and regeneration were studied. Favorable conditions for formation of protoplasts from Saccharomyces cerevisiae D-71 were : treatment of the cells at late-exponential phase with 2-mercaptoethanol (l% v/v) for 10 minutes in the presence of 0.5M sorbitol, then incubation for 60 minutes in the set medium containing Zymolyase-20T (4mg/$m\ell$) ; and from Zygosaccharomyces rouxii SR-S were : treatment of the cells at mid-exponential phase with 2-mercaptoethanol (1% v/v) for 10 minutes in the presence of 0.5M or 1M mannitol, then incubation for 120 minutes in the set medium containing Zymolyase-20T(4mg/$m\ell$). The protoplasts of parental cells were fused in the presence of 20mM CaCl$_2$, 0.5M sorbitol and 40% of polyethyleneglycol (M.W 4000), then fusants obtained were selected as regenerated colonies which embedded and grown in the minimal medium containing 3% of agar. The frequencies of fusant formation were 1.2$\times$10$^{-6}$ to 9.1$\times$10$^{-6}$ for the regenerated protoplast.

• Journal of Mushroom
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• v.20 no.2
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• pp.50-54
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• 2022

This study was conducted to reduce the phenomenon of the biased cultivation of certain mushroom varieties and to develop a competitive variety of Grifola frondosa. We developed the first Korean white commercial mushroom strain, 'Bakyeon', by crossing monokaryons derived from brown strains. We have collected and tested the characteristics of mushrooms from domestic and international genetic resources since 2018. We bred the unique domestic variety, 'Bakyeon', which has the following characteristics. The optimal temperature for mycelial growth was 25~28℃ and the optimal temperature for fruit body growth was 16~18℃. The new variety was similar to the control variety (Daebak) in terms of the pileus, which formed a pine cone shape, and the number of days of cultivation. The yield was 94.1 g/bottle, which was 23% lower than the 108.5 g/bottle yield of the control variety. When incubating the parent and control varieties, the replacement line was clear. Moreover, polymerase chain reaction analysis of mycelial DNA resulted in different band patterns between the parent and control varieties, confirming the hybrid species.

• Korean Journal of Poultry Science
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• v.43 no.3
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• pp.177-189
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• 2016

This study was conducted to verify the relationships between the expression values of stress-related markers and their production performances in 25 strains of Korean domestic chicken breeds. For stress response markers, the amount of telomeric DNA; expression levels of heat shock protein (HSP)-70, $HSP-90{\alpha}$, and $HSP-90{\beta}$; and comet scores were analyzed. Production performances were measured by the survival rate, body weights, days at first egg laying, egg weight and hen housed egg production. The results showed that the production traits and values of stress-related markers showed significant differences between strains. In general, the stress response of pure bred chickens with heavy weights was relatively high, while that of hybrid chickens with light weights was relatively low. The correlation coefficients between telomere contents and body weights showed that there were weak negative relationships. However, the correlations of telomere content with the survival rate and egg production were weakly positive after 20 weeks old. The expression levels of HSP genes and DNA damage rate (comet scores) were positively correlated to body weight, but were negatively correlated to the survival rate and egg production. The results implied that increasing body weight was associated with increasing HSPs expression and the DNA damage rate was associated with decreasing telomere content. In addition, increasing HSPs expression and the DNA damage rate decreased the survival rate and egg production, but the relationships with the telomere content was the reverse. Correlations among the stress-related markers showed that there were significant correlation coefficients between all of the marker values. HSPs expression was negatively correlated to the telomere content, while it was positively correlated to the DNA damage rate. There was a highly negative correlation between the telomere content and DNA damage rate. In conclusion, increasing the HSP values and DNA damage rate can promote telomere reduction, which led to a decrease in disease resistance and robustness of the chicken. Thus, increasing the stress response was verified to adversely affect the laying performance and viability of chickens.

• Journal of Sericultural and Entomological Science
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• v.41 no.1
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• pp.20-28
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• 1999

Color qualities investigated on the basis of Munsell code and Korean standard color code for the cocoons from various strain of mulberry silkworm, Bombyx mori. 16 of different color qualities were identified from 21 of original silworm strains, and determinated international name with the revision of Korean color name for cocoon. The various cocoon color confirmed on the sphere from 567 to 593 nm wavelength, 78% of those located at the region about 580 nm (575~584) of sensitive "color difference limen". Y gene engaged broad ranges of wavelength (575~593 nm) in the color expression, by contrast with other genes of Pk (593 nm), F (584~593), Grc and relative G group (567~570 nm), on the transmission of carotenoid or flavonoid color substance. YC gene expression by original silk worm strain was also distinguished by those variation of specific yellow than other colors from Grc, GaGb, Gc, and YPkF. Appearance of chrome yellow cocoon was dominant than other yellow in the cross among vivid yellow group. F1 of pin${\times}$green produced the cocoon of yellow such as "additive mixture" as color light, however, most of the hybrid between yellow cocoon showed the color similar to "subtractive mixture" as a mixture of dyestuff. Hybrid cocoons among yellow or green colors were decreased their hue, value, and chroma, than those of parent. Diallel cross among the strain of various green cocoon suggest the existence of Grc, Ga, Gb, Gc genes. Cream colored cocoon of B. mandarina was differed from other yellow cocoon of Bobyx mori B. mori. Y$^A$ with Ymc showed the similar role of Y with C, therefore, segregated yellow cocoon from the B. mori${\times}$B. mandarina (+$^YC/Y^AYmc$). YC expression of $Y^AY$mc genes might be suppressed by deficiency of outer layer sericin on the middle division of silk giand in the B. mandarina.