• Research in Plant Disease
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• v.9 no.2
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• pp.85-88
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• 2003

A sclerotinia rot of Water cress (Oenanthe javanica) occurred in the commerical farmers field at Garye-myon, Uiryeong-gun, Gyeongnam Province, Korea, 2002. The typical symptoms appeared on leaves and stems. At first, the infected leaves or stems turned dark green later become watery soft rotted; white fluffy mycelia grew from the lesion, later formed black sclerotia. Sclerotia on the infected plants and PDA medium were globose to cylindrical or irregular in shape and 1.0~10.7 ${\times}$1.0~7.6 mm in size. Cup-shaped aphothecia with numerous asci were formed from sclerotinia and the size were 0.4~1.6 cm in diameter. Asci with 8 spores were cylindrical and 74~236 ${\times}$ 4.2~24.8 m in size. Ascospores of one cell were hyaline, ellipsoid to ovoid in shape, and 8.3~12.4 ${\times}$ 3.6~7.2 m in size. The optimum temperature for mycelial growth was $25^{\circ}C$ , and sclerotinia forma-tion was between 15~$20^{\circ}C$. On the basis of mycological characteristics and pathogenecity test to host plants, the fungus was identified as Sclerotinia sclerotiorum. This is the first report of Sclerotinia sclerotiorum caused sclerotinia rot on Oenanthe javanica caused by in Korea.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.454-458
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• 2006

HSF1 is the heat shock transcription factor in Saccharomyces cerevisiae. S. cerevisiae KNU5377 can ferment at high temperature such as $40^{\b{o}}C$. We have been the subjects of intense study because Hsf1p mediates gene expression not only to heat shock, but to a variety of cellular and environmental stress challenges. Basing these facts, we firstly tried to construct the hsf1 gene-deleted mutant. PCR-method for fast production of gene disruption cassette was introduced in a thermotolerant yeast S. cerevisiae KNU5377, which allowed the addition of short flanking homology region as short as 45 bp suffice to mediate homologous recombination to kanMX module. Such a cassette is composed of linking genomic DNA of target gene to the selectable marker kanMX4 that confers geneticin (G418) resistance in yeast. That module is extensively used for PCR-based gene replacement of target gene in the laboratory strains. We describe here the generation of hsf1 gene disruption construction using PCR product of selectable marker with primers that provide homology to the hsf1 gene following separation of haploid strain in wild type yeast S. cerevisiae KNU5377. Yeast deletion overview containing replace cassette module, deletion mutant construction and strain confirmation in this study used Saccharomyces Genome Deletion Project (http:://www-sequence.standard.edu/group/yeast_deletion_project). This mutant by genetic manipulation of wild type yeast KNU5377 strain will provide a good system for analyzing the research of the molecular biology underlying their physiology and metabolic process under fermentation and improvement of their fermentative properties.

• Food Science and Preservation
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• v.11 no.3
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• pp.411-416
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• 2004

Botanical antimicrobial agent-grapefruit seed extract mixture(BAAG), which could be applied to the preparation of antimicrobial packaging paper, was investigated in order to prove the preservative function of fruits and vegetables. HAAG showed remarkable antimicrobial effects against Fusarium solani Botrytis cinerea, Pencillium crustosum, Erwinia carotovora, Phoma destructiva and Alternaria radicina causing the postharvest decay of fruits and vegetables. We have examined that HAAG could inhibit the growth of microorganims when treated with more than 500 $\mu$g/mL concentration. The activities of HAAG were stable in the wide spectrum of pH and temperature. Direct visualization of microbial cells by using scanning electron microscope showed the loss of microbial cell membrane function, which was destroyed by treating with the dilute solutions of HAAG. We could confirm that HAAG be an antimicrobial agent for the preparation of antimicrobial packaging paper.

• Applied Biological Chemistry
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• v.27 no.2
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• pp.55-63
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• 1984

Lethal effect on Chinese radish Kimchi was investigated by using a pilot scale Kimchi pasteurizer. A simulation model was presented so as to predict the change in viable cell concentration of the Kimchi during pasteurization. D values of microorganisms in the Kimchi were found to be 2.21, 1.62, 0.73, 0.39 and 0.21min at 60, 64, 70, 75 and $80^{\circ}C$, correspondingly, and thereby z value was $19^{\circ}C$. One cycle time required was 0.99min at flow rate of 4 l/min. The ratio of lethality in preheating section to total lethality was 0.3 and the ratio of lethality in holding, precooling and cooling sections to total lethality was 0.7. The experimental data were in good agreement with the values simulated by two model equations to which linear and exponential temperature profiles were applied at $65^{\circ}C\;and\;70^{\circ}C$ in holding section.

• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.356-362
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• 2014

Wear and corrosion of the engine parts surrounded with combustion chamber is more serious compared to the other parts of the engine because temperature of the exhaust gas in a combustion chamber is getting higher and higher with increasing of using the heavy oil of low quality. Therefore, an optimum repair weldment as well as an available choice of the base metal for these parts are very important to prolong their lifetime in a economical point of view. It reported that there was an experimental result for repair weldment on the forged steel which would be generally used with piston crown material, however, it is considered that there is no study for the repair weldment on the cast steel of piston crown material. In this study, four types of electrodes such as 1.25Cr-0.5Mo, 0.5Mo Inconel 625 and 718 were welded with SMAW and GTAW methods on the cast steel which would be generally used with piston crown material. And the corrosion properties of weld metal, heat affected zone and base metal were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% $H_2SO_4$ solution. In the cases of Inconel 625, 718, the weld metals and base metals exhibited the best and worst corrosion resistance respectively, however, 1.25Cr-0.5Mo and 0.5Mo indicated that corrosion resistance of the base metal was better than the weld metal. And the weld metal welded with electrodes of Inconel 625 revealed the best corrosion resistance among the electrodes, and Inconel 718 followed the Inconel 625. Hardness relatively also indicated higher value in the weld metal compared to heat affected zone and base metal. In particular, Inconel 718 indicated the highest value of hardness compared to other electrodes in the heat affected zone.

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.323-327
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• 2003

Microwave dielectric properties of (P $b_{0.4}$C $a_{0.6}$)[($Fe_{\frac{1}{2}}$N $b_{\frac{1}{2}}$)$_{1-x}$ (M $g_{1}$ 3/N $b_{2}$ 3/)x] $O_3$ (PCFMN) ceramics were investigated as a function of (M $g_{1}$ 3/N $b_{2}$ 3/)$^{4+}$ content (0.1$\leq$x$\leq$0.8). A single perovskite phase with the cubic structure was obtained through the given composition range. The unit cell volume was increased with (M $g_{1}$ 3/N $b_{2}$ 3/)$^{4+}$, due to the larger average ionic size of (M $g_{1}$ 3/N $b_{2}$ 3/)$^{4+}$ than that of ($Fe_{\frac{1}{2}}$N $b_{\frac{1}{2}}$)$^{4+}$ for B-site ion. Dielectric constant (K) and Temperature Coefficient of Resonant Frequency(TCF) of PCFMN ceramics were dependent on (M $g_{1}$ 3/N $b_{2}$ 3/)$^{4+}$ content due to the decrease of ionic polarizability and B-site bond valence, respectively. Qf value was decreased with (M $g_{1}$ 3/N $b_{2}$ 3/)$^{4+}$ content due to the decrease of grain size. Typically, K of 73.56, Qf of 5,074 GHz and TCF of -6.45 ppm/$^{\circ}C$ were obtained for the specimens with x=0.4 sintered at 125$0^{\circ}C$ for 3 h.125$0^{\circ}C$ for 3 h.

• KSBB Journal
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• v.14 no.2
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• pp.153-159
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• 1999

Fifteen microbes have been isolated from Jangja pond in Kuri-Si, Kyeonggi-Do. Among them, two strains showed excellent COD removal from wastewater, which were named Pseudomonas sp. BLP2052 and Flavobacterium sp. BLP20515, respectively. Optimal pH and temperature for the cell growth were 7.0 and $30^{\circ}C$ for both strains. Pseudomonas sp. BLP2052 and Flavobacterium sp. BLP20515 was applied to the reactor to treat wastewater and 66.0% and 65.7% COD (chemical oxygen demand) removal was achieved, respectively. Comparing these results to the case of applying mixed microbes present in Jangja pond, COD removal rate was 15% less. But when adding the selected microbes to the wastewater containing mixed microbes, COD removal rate increased by 5%. After 84 hour operation, we achieved 85.6% COD removal. When inhibitors were added less than 100 ppm, during the microbial wastewater treatment, Fe, Zn, Al, phenol and Cr influenced microbial activity more deterioratively in order. In the case of over 300 pm, Cr, Fe, Zn, Al and phenol showed severe deteriorative effect in order.

• KSBB Journal
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• v.16 no.5
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• pp.466-473
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• 2001

A bacterium was isolated from soils in Suwon, Korea for the purpose of H$_2$S removal using a biofilter system. The isolate was gram-negative, rod-shaped, catalase-positive, motile, and the isolated bacterium showed a positve in utilizing energy sources including citrate, mannitol, sucrose, fructors, and trehalsoe. Based on its biochemical characteristics it was identified as Burkholderia(Pseudomonas) cepacia. The growth rate of the bacterium in thiosulfate medium with yeast extract was 0.15 hr$\^$-1/ and generation time was 4.6 hr. The cell productivity was 8.05 mg/L$.$h and the isolate grew logarithmically up to 12 hr. The maximum rate of sulfur oxidation was 0.18 g-S/L$.$h. The optimum pH and temperature for the growth of the bacterium were 7.0 and 30$\^{C}$, respectively. The pH range for the growth of B. cepacia was 5.0-8.0. The oxidation rate of thiosulfate was lowered by a substrate thiosulfate when the concentration was higher than 0.12 M. both growth rate and sulfur oxidation rate of Burkholderia(Pseudomonas) cepacia was enhanced about 1.5 times with the addition of 0.2% yeast extract. The removal of hydrogen sulfide was investigated by immobilized B. cepacia with Ca-alginate. The maximum rate removal for H$_2$S was 6.25 g$.$㎤ $.$h$\^$-1/ when 12 L/h of flow rate was supplied. From this study suggest the immobilized B. cepacia could have a potential for H$_2$S removal.

• KSBB Journal
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• v.25 no.3
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• pp.289-296
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• 2010

Lectins are carbohydrate-binding and a cell-agglutinating proteins, and are concerted with a plants defence mechanism. In particular, chitin-binding lectins in locular fluid of cherry tomato fruit seemed to have a role in defending plants against fungi. The antifungal activity using lectin isolated from locular fluid of cherry tomato fruit was measured in the plant pathogen Cladosporium cucumerinum, Monosporascus cannonballus, Fusarium oxysporum, and Rhizoctonia solani. Amoung the four strains, a potent antifungal activity was detected in Cladosporium cucumerinum and Monosporascus cannonballus, not in Fusarium oxysporum, and Rhizoctonia solani. The molecular weight of this lectin isolated as double protein bands by SDS-PAGE was calculated to be 87 kDa and 47 kDa from the relative mobilities compared with those of reference molecular weight markers. The isolated lectin agglutinated human red blood cells (A, B, AB, O) treated with trypsin, and the most activity was found at B. The optimal temperature of isolated lectin was at $30^{\circ}C$. For the thermal stability, lectin was stable at $20-80^{\circ}C$. The optimal pH of this lectin was at 7.2, and showed complete loss below pH 9.0.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.542-550
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• 2016

This study was carried out to investigate the optimal processing conditions for odor removal and maximal antioxidant effects of oyster (Crassostrea gigas) hydrolysate. The optimal hydrolysis conditions were 3.3% neutrase as the protease, $50^{\circ}C$ as the hydrolysis temperature, and 8.3 h as the hydrolysis time. Fish odor of enzymatic oyster hydrolysate was greatly reduced during Saccharomyces cerevisiae fermentation at $24^{\circ}C$ with 0.5% glucose. The protein content of the fermentation product from oyster hydrolysate powder was 25.7%, which contained the major amino acids Glu, Asp, Lys, Arg, Gly, and Ala, whereas Leu, Ala, Phe, Val, and Tau were abundant free amino acids. The important minor minerals were Zn and Fe. Toxicity against Chang cells was not observed in the fermentation product from the oyster hydrolysate up to $200{\mu}g/mL$. The results suggest that fermentation with S. cerevisiae could reduce the fish odor of enzymatic oyster hydrolysate. The hydrolysate has potential application as a food ingredients and nutraceutical.