• The Korean Journal of Mycology
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• v.9 no.2
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• pp.93-97
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• 1981

The new strains of Mycogone perniciosa which could attack cream colored mushroom were collected and tested to find out their characteristics in comparison with the original strains. The optimum temperature for mycelial growth was $25^{\circ}C$, showing no difference between strains, but optimum pH was 6.0 for the original strains and pH 7.0 for the new ones. New strains did not survive at $50^{\circ}C$ for 60 minutes while original ones 40 minutes. Delan and Hamai were effective for controlling new strains and the mushroom strains which have scales showed resistance to the new strains of Mt. perniciosa regardless of the mushroom colors.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.76-82
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• 2003

To prepare evolved PHB depolymerase with increased activity for PHB or P(3HB-co-3HV) compared to the activity of the original PHB depolymerase from Alcaligenes faecalis T1, random mutation of the cloned PHB depolymerase gene was performed by using a DNA shuffling method. A library of mutated PHB depolymerase genes from A. faecalis T1 was fused to the ice nucleation protein (INP) gene from Pseudomonas syringae in pJHCl 1 and approximately 7,000 transformants were isolated. Using M9 minimal medium containing PHB or P(3HB-co-3HV) as the carbon source, mutants showing alteration in PHB depolymerase activity were selected from the transformants. The PHB depolymease activity of the transformants was confirmed by the formation of halo around colony and the turbidity decrease tests using culture supermatants. The catalytic activity of PHB depolymerase of the best mutant II-4 for PHB or P(3HB-co-13 mol% 3HV) was approximately 1.8-fold and 3.2-fold, respectively, higher than that of the original PHB depolymerase. DNA sequence analysis revealed that three amino acid residues (Ala209Val, Leu258Phe, and Asp263Thr) were substituted in II-4. From the mutational analysis, it was presumed that the substitution of amino acids near catalytic triad to more hydrophobic amino acids enhance the catalytic activity of PHB depolymerase from A. faecalis T1.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.448-452
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• 2015

The bacterial strain that was isolated from chinese cabbage rhizosphere, showed inhibition of yeast growth. This strain was identified as Pseudomonas fluorescens BB2 by API 20NE test and 16S rRNA gene sequence analysis. P. fluorescens BB2 strain produced antibiotics against yeast as a secondary metabolite effectively when the culture was carried out in YM medium with 3% glucose at $20^{\circ}C$. The protein antibiotic of BB2 strain which was concentrated by ammonium sulfate precipitation and n-butanol extraction inhibited the growth of yeast with the minimal inhibitory concentration of $10{\mu}g/ml$ against Candida albicans KCTC 7965, and the growth of yeast was completely inhibited at $80{\mu}g/ml$. The hydrophilic fraction of n-butanol extraction inhibited the growth of Bacillus cereus ATCC 21366, showed orange halo on chrome azurol S plate, which means the fraction contained iron chelating siderophore. The results of crystal violet uptake through the cell membrane showed that membrane permeability was increased about 9% than control, when the concentration of hydrophobic antibiotic against yeast C. albicans was $60{\mu}g/ml$. As a result, the antibiotic produced by P. fluorescens BB2 against yeast Candida is considered antimicrobial peptide, and this is the first report in the genus Pseudomonas.

• Journal of Life Science
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• v.20 no.8
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• pp.1249-1253
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• 2010

Sericin is a type of high molecular weight water-soluble glycoprotein surrounding fibroin (silk protein) that has been used as a cell culture supplement and accelerates cell proliferation in various serum-free media. The purpose of this study was to investigate the enhancing effect of thyroglobulin (Tg) secretion by sericin in thyrocytes, FRTL-5 cells. While Tg-mRNA expression was not enhanced, a secreted form of Tg was obviously increased by sericin. In this status, expression of both endoplasmic reticulum (ER) molecular chaperones (Bip & calreticulin) and ER membrane proteins (IRE1, PERK & ATF6) was enhanced. The proximal step of IRE1, XBP1 mRNA splicing was slightly detected however, the proximal step of PERK, phosphorylation of $eIF2{\alpha}$, was changeless. In addition, sericin enhanced cell viability by the MTT assay. The above results showing the ability of sericin to promote protein production demonstrated its potential usefulness as a new biomaterial.

• Journal of Korean Society of Forest Science
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• v.107 no.3
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• pp.258-265
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• 2018

This study was conducted to investigate the effective cryopreservation condition of Potentilla discolor Bunge, a rare native plant. Seed viability was more than 80% in PVS2 and PVS3 solution treatments. Seed viability was higher in PVS3 than PVS2 treatment. Seed viability was lower than control in spite of sucrose pretreatment. The germination rate was 95% at 60 min of PVS2 treatment and 30 min of PVS3 treatment but the germination rate was low at other treatments. The growth of the seedling wasn't doing that of the control except for treat PVS2 and PVS3 solution for 30 min. There was no statistically significant difference between the encapsulation method and the vitrification method in the seedling growth between the two cryogenic storage methods. This study is expected to be applied to future conservation methods of Potentilla discolor.

• Journal of Korean Society of Forest Science
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• v.39 no.1
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• pp.57-63
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• 1978

Enzymatic hydrolysis of the substrate from Alnus hirsuta (Spach) Rupr (8-14years) was investigated using cellulase preparations of Trichoderma viride Pers. ex. Fr. SANK 16374 and conduced on the optimum reaction conditions of the cellulase on saccharification. The crude cellulase was produced by the submerged culture process and produced in the culture fluid was salted out quantitatively by the use of ammonium sulfate. The method of delignification from wood(Saw dust) was treated by the peracetic acid (PA) method. Reducing sugar was determined by the dinitrosalicylic acid (DNS) method. The results were summerized as follows; 1. The optimum pH of cellulase was 5.0 and the range of stability with respect to pH was generally from 4.0 to 6.0 2. The optimum temperature of cellulase was generally $40^{\circ}C$, but reducing sugar formation did not show significent differences at 5% levels in the reaction temperature from $40^{\circ}C$ to $50^{\circ}C$. 3. The redusing sugar were increased with increase of cellulase concentration. 4. The reducing sugar were decreased with increase of substrate concentration. 5. Fructose was a very good inhibitor of the enzyme from Trichoderma viride, but glucose inhibition was generally weak.

• Journal of Environmental Health Sciences
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• v.31 no.5 s.86
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• pp.360-364
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• 2005

When rapeseed oil as the carbon source was used for tylosin production from Streptomyces fradiae TP-1239 was very sensitive to oleic acid. Cell growth was restrained by adding 0.8 g/l of oleic acid to the culture broth. Mutant strain TM-224-1 resistant to 1.2 g/l of oleic acid was obtained by screening in solid and liquid media containing oleic acid. The uptake rate of oleic acid by TM-224-1 was approximately 3.8 fold higher than the parent strain. For comparing the TM-224-1 and the parent strain, batch cultures were carried out in a jar fermentor. Cell growth of TM-224-1 strain was higher than the parent strain after two days of culturing. However, after four days of culturing, it was similar to that of the parent strain. The amount of rapeseed oil consumed by TM-224-1 and the parent strain were 60.5 and 78.2 g/l, respectively. The production and yield of tylosin was aproximately 2.0 and 3.2 fold higher than the parent strain, respectively. From these results, it was concluded that this mutant, which was resistant to oleic acid, has improved tylosin production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.12
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• pp.1633-1636
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• 2007

This study was carried out to enhance the stability and activity of polygalacturonase (PGase) purified from Kluyveromyces marxianus IFO 0288. Gums such as xanthan gum, guar gum, and locust bean gum were capable of increasing the catalytic stability and activity of the PGase. At $30^{\circ}C$, the rate constants for the inactivation of the PGase with xanthan gum, guar gum, and locust bean gum were estimated to be $0.0003min^{-1}$, below $0.0001min^{-1},\;and\;0.0001min^{-1}$ respectively, whereas control was estimated to be $0.0082min^{-1}$. The yield of the maceration reaction catalyzed by the PGase for the production of carrot single cells increased by 13% in the presence of guar gum, where the relative enzyme activity supplemented with guar gum was two-fold greater than that of the PGase alone.

• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.206-211
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• 2008

Streptococcus pneumoniae is a common cause of acute otitis media, sinusitis, pneumonia, and the invasive bacterial infections in children. Rarely, S. pneumoniae is an uncommon cause of hemolytic-uremic syndrome (HUS). We report a 33 month-old girl who presented with pneumonia, and subsequently developed HUS. Her pulmonary infection was complicated by necrotizing pneumonia and acute respiratory distress syndrome. Cultures from blood and pleural fluid grew S. pneumoniae, serotype 19A. She was treated with antibiotics, dialysis and mechanical ventilatory support. She was discharged with normal renal function after 2 months of management. She remained healthy without renal complications at the 5 year follow-up visit.

• Research in Plant Disease
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• v.20 no.2
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• pp.87-94
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• 2014

The fungus Cylindrocarpon destructans is the cause of root rot in many ginseng production areas in Korea. A total of 57 isolates of C. destructans were recovered from diseased roots in a survey of ginseng-growing fields from 2011-2012. Among these isolates, 37% were classified as highly virulent (causing lesions on unwounded mature roots) and 61% were weakly virulent(causing lesions only on previously wounded roots). Radial growth of highly and weakly virulent isolates on potato dextrose agar was highest at $20^{\circ}C$ and there was no growth at $35^{\circ}C$. Mycelial mass production was significantly (P = 0.05) lower at pH 7.0 compared with pH 5.0. To study the effects of pH (5.0 and 7.0) and wounding on disease development, ginseng roots were grown hydroponically in nutrient solution. Lesions were significantly larger (P < 0.01) at pH 5.0 compared with pH 7.0 and wounding enhanced disease by a highly virulent isolate at both pHs. In artificially infested soil, 2-yearold ginseng roots were most susceptible to Cylindrocarpon root rot among all root ages tested (1 to 4 years) when evaluated using a combined scale of disease incidence and severity. Root rot severity was significantly (P<0.05) enhanced by increasing the inoculum density from $3.5{\times}10^2cfu/g$ of soil to $2.0{\times}10^3cfu/g$ of soil.