• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.90-96
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• 2004

A synthetic defined medium, fortified with amino acids, was developed for the stable production of the kringle fragments of human apolipoprotein(a) (apo(a)), rhLK68. Using a complex rich medium containing yeast extract and a high-cell-density fed-batch culture, the expression level of rhLK68 reached 17% of the total cellular protein, which corresponded to $5\;g\;l^{-1}$ of the culture. To replace the complex media with chemically defined media, several amino acids that positively affect cell growth and gene expression were chosen by a statistical method. The various combinations of the selected amino acids were tested for its fortifying effect on a minimal defined medium. When glutamine only was added, the overall expression level of rhLK68 reached 93% of the complex rich medium increasing the specific expression level by 22.4% and decreasing the cell growth by 24%. Moreover, the addition of glutamine resulted in a 2-fold increase in the concentration of rhLK68 in the culture broth, compared with the minimal defined medium. The synthetic defined media developed in this study could be generally applied to high-cell-density cultures of the recombinant Escherichia coli BL21(DE3), especially for the production of therapeutic proteins that require a strict quality control of the culture media and fermentation processes.

• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.145-152
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• 1999

Brettanomyces custersii CBS 5512 which has reported as a thermotolerant glucose-cellobiose co-fermentable yeast strain was mutated with UV and NTG to improve ethanol yield at higher than 4$0^{\circ}C$ B. custersii H1-23, H1-39, H1-55 and H1062 were finally selected for hyper-fermentable strains at higher than 4$0^{\circ}C$ from thermotolerant 7510 colonies through 5th selection. Among the selected strains, H1-39 mutant had better fermentability at 4$0^{\circ}C$ and 43$^{\circ}C$ from different concentrations of glucose. H1-39 and H1-23 mutants yielded more than 70% of the theoretical ethanol yield in 4 and 8% mixed sugars at above 4$0^{\circ}C$, which was 5-11% higher than those by original strain. Especially, H1-39 mutant had better fermentability in 4% mixed sugar. It showed 78.5% of the theoretical yield at 4$0^{\circ}C$ and 72.2% of the theoretical yield at 43$^{\circ}C$. On the other hand, theoretical yield of ethanol by H1-39 mutant in 8% mixed sugar at 4$0^{\circ}C$ and 43$^{\circ}C$ were 75.2% and 70.2%, respectively. Theses values increased up to 7-11% as compared to those by orginal strain. By the simultaneous saccharification and fermentation, ethanol production by H1-39 mutant increased up to more than 23% as compared to that by original strain.

• Journal of Life Science
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• v.12 no.2
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• pp.219-225
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• 2002

The organization of eukayotic chromatin into specific conformation that are associated with transcription, replication, reapir and other nuclear processes are achieved via a series of DNA-protein interaction. These interactions are mediated by a range of DNA-binding domains such as SAP domain et at. By searching S. pombe genomic DNA database, we have found a gene named SAPuvs (SAP UV Sensitive) whose amino acid sequence is in part similar to SAP domain of Arabidopsis poly (ADP-ribose) polymerase and Ku7O. Knock-out cell of S. pombe SAPuvs gene was constructed using Ura4 as a selection marker. Survival analysis of knock-out cell indicated that treatment with UV significantly reduces the survival compared to wild type cell. Potentiation of MMS-induced cytotoxicity by 3AB post-treatment was observed in wild type cells, but not in knock-out cells. These data suggested that the protein encoded by SAPuvs gene is associated with chromatin reorganization during DNA repair.

• Korean Journal of Food Science and Technology
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• v.2 no.2
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• pp.56-59
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• 1970

Although there are no oil wells in Korea, yet more than 900 strains of petroleum hydrocarbon utilizing microorganisms have been isolated from 357 soil and sewage samples collected from oil depots and other sources there. From these samples 7 strains of yeast were selected on the basis of their superior cell yields. Five of them were identified as Candida tropicalis, the other being Candida lipolitica and Torulopis sp. Of the selected strains the mass doubling time is $2.9{\sim}4.5$ hrs., the yield is $6.5{\sim}16.3\;g/l$; the conversion rate of crude petroleum substrate into the microbial mass is $7.8{\sim}19.3%$; and protein content of dried cells is $48.8{\sim}59.8%$.

• Journal of environmental and Sanitary engineering
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• v.4 no.1 s.6
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• pp.17-28
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• 1989

Having studied the production of monoclonal antibodies for developing a diagnosis medicine which shall be detected by a high-sensitivity test by using Rhodotorula rubra as a fungi-host which had been extracted through biochemical tests and follow-up examinations on Yeast-like fungi obtained from pulmonary tissues of pulmonary tuberculosis patients who had been in Kong ju National Tuberculosis Hospital from Jun. to Dec. in 1987, I. have gained such results as follows: 1. The fusion rate was influenced by feeder cell layers, cell density and time required to the cell fusion with cells in myelona subculture. 2. The fusion rate did not show any significant difference when the cell was applyed with two molecular weights, i.e., 1500 and 4000, of polyethylene glycol. 3. Fused cells after the addition of HAT selection media were bright and round, whereas unfused myelona cells and spleen cells were shrunk and granulated. 4. The cell fusion rate turned out to be about $57.2\%$(150 wells / 264 wells). 5. $10\%$(15 wells / 150 wells) of the positive reaction was detected in monoclonal antibody screening. 6. The titer which had reacted positively to Rhodotorula rubra fungal-host was 800 times in density after the gradual dilution of the produced monoclonal antibodies with Indirect ELISA method. 7. The Strongest specific reaction came out after the peroxidase labelled anti-human Immunogobulin had been applyed to Rhodotorula rubra for activating its nature after making drift with Carbonate-bicarbonate buffer (pH 9.6) and drying completely.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1819-1825
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• 2008

Degradation and glucose production from wood chips of white pine (Pinus strobus) and tulip tree (Liriodendron tulipifera) by several white rot fungi were investigated. The highest weight losses from 4 g of wood chips of P. strobus and L. tulipifera by the fungal degradation on yeast extract-malt extract-glucose agar medium were 38% of Irpex lacteus and 93.7% of Trametes versicolor MrP 1 after 90 days, respectively. When 4 g of wood chips of P. strobus and L. tulipifera biodegraded for 30 days were treated with cellulase, glucose was recovered at the highest values of 106 mg/g degraded wood by I. lacteus and 450 mg/g degraded wood by T. versicolor. The weight loss of 10 g of wood chip of L. tulipifera by T. versicolor on the nutrient non-added agar under the nonsterile conditions was 35% during 7 weeks of incubation, and the cumulative amount of glucose produced during this period was 239 mg without cellulase treatment. The activities of ligninolytic enzymes (lignin peroxidase, manganese peroxidase, and laccase) of fungi tested did not show a high correlation with degradation of the wood chips and subsequent glucose formation. These results suggest that the selection of proper wood species and fungal strain and optimization of glucose recovery are all necessary for the fungal pretreatment of woody biomass as a carbon substrate.

• Journal of Microbiology
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• v.45 no.3
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• pp.227-233
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• 2007

In budding yeast, septin plays as a scaffold to recruits protein components and regulates crucial cellular events including bud site selection, bud morphogenesis, Cdc28 activation pathway, and cytokinesis. Phosphorylation of Bni5 isolated as a suppressor for septin defect is essential to Swe1-dependent regulation of bud morphogenesis and mitotic entry. The mechanism by which Bni5 regulates normal septin function is not completely understood. Here, we provide evidence that Bni5 phosphorylation is important for interaction with septin component Cdc11 and for timely delocalization from septin filament at late mitosis. Phosphorylation-deficient bni5-4A was synthetically lethal with $hof1{\Delta}$. bni5-4A cells had defective structure of septin ring and connected cell morphology, indicative of defects in cytokinesis. Two-hybrid analysis revealed that bni5-4A has a defect in direct interaction with Cdc11 and Cdc12. GFP-tagged bni5-4A was normally localized at mother-bud neck of budded cells before middle of mitosis. In contrast, at large-budded telophase cells, bni5-4A-GFP was defective in localization and disappeared from the neck approximately 2 min earlier than that of wild type, as evidenced by time-lapse analysis. Therefore, earlier delocalization of bni5-4A from septin filament is consistent with phosphorylation-dependent interaction with the septin component. These results suggest that timely de localization of Bni5 by phosphorylation is important for septin function and regulation of cytokinesis.

• Korean Journal of Organic Agriculture
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• v.10 no.4
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• pp.47-60
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• 2002

'Probiotics' as a live microbial feed supplementation which beneficially affects the host animal by improving its microbial balance and it is known to as a substitue for antibiotics in livestock feed industry. Lactic acid bacteria as a Lactobacillus sp. is formed acid and decrease pH in gastro-intestine that is result in suppress harmful microorganism. Lactobacillus sp. also produces vitamin and a variety amino acids. Yeast as a saccharomyces sp. secretes digestive enzymes, decreases ammonia emission and increases feed palatability by alcohol and glutamic acid. The effects of dietary probiotics in monogastric animals that improve weight gain and feed efficiency ratio and decrease diarrhea accurence frequency in pigs. Also, probiotics increase egg production ratio and beneficial microorganisms in laying hens. In broiler, they have more gain weight and lower blood cholesterol concentrations by probiotics. However, the other study reported probiotics supplementation in animal diets has no effect on ADG, G/F or performance. Thus, future study in these area will allow for more efficient use of the probiotics, selection of more superior microorganism and development of more efficient environment-friendly probiotics like a photosynthetic bacteria.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.82-92
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• 1976

The study was carried out to investigate the changes of the various chemical components and the microflora during the aging period of Korean navive Kochuzang. (Red pepper soybean paste) Korean native maeju loaves were separated into surface and inner parts. Three kinds of Korean native Kochuzang were prepared from surface part, inner part, and ordinary of maeju. The selection and the indentification of the high enzyme producing strains from the microflora and characteristics of their enzymes were studied. I. The changes of the various chemical components during the aging period of Kochuzang. 1) The changes of pH in the 3 kinds of Kochuzang displayed rapid decrease for the first 10 days after preparing and gradual curve of decrease until 60 days, but slight increase for the next 30 days. The pH of the surface part Kochuzang was lower than that of inner part or ordinary Kochuzang. 2) The total acid contents in the 3 kinds of Kochuzang showed gradual increase until the 60 days but it slowly reduced after this time. 3) The total nitrogen contents in the 3 kind of Kochuzang showed gradual inerease up to the 60 days, but slight decrease after this time. 4) The changes of trichloroacetic acid soluble nitrogen in the 3 kinds of Kochuzang showed a remarkable increase for the first 10 days, however gradual increase after this time. 5) The increase of amino nitrogen contents in the 3 kinds of Kochuzang seemed to be remarkable until the first 30 days, however to be less remarkable after this time. 6) The contents of reducing sugar in the 3 kinds of Kochuzang showed remarkable increase until the first 50 days and it slowly reduced after this time. II. The changes of microflora during the aging period of Kochuzang. 1) Aerobic, anaerobic bacteria and mold in the 3 kinds of Kochuzang were increased until the first 30 to 40 days, but they were reduced after this time. 2) No yeast in the three kinds of Kochuzang appeared until the first 20 days. Yeast were proved to grow, when the pH value was decreased below 5.4 after the 30 days. Yeasts in the surface part and ordinary Kochuzang were gradually increased and those in the inner part Kochuzang were decreased as aging. III. The selection and identification of high amylase and protease producing strains from the microflora during the aging period of Kochuzang. 1) The amylase and protease highly producing strains from microflora were identified as Bacillus subtilis-P, Bacillus subtilis-G, Bacillus licheniformis-K, Aspergillus oryzae-B. 2) Amylase activity of Aspergillus oryzae-B was highest among the strains and the strains in order of the higher activity to the lower one were Bacillus subtilis-P Bacillus licheniformis-K, Bacillus subtilis-G. Protease activities of Aspergillus oryzae-B and Bacillus subtilis-P were about the same and the strains in order of the higher activity to the lower one were Bacillus licheniformis-K, Bacillus subtilis-G. 3) Amylase activity was inhibited more than protease activity was with NaCl concentration. Amylase activity was inhibited by 45 to 65 percent and protease activity by 40 to 46 percent at the concentration of 15 percent NaCl, which was the average concentration of NaCl in Kochuzang.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.261-265
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• 2010

Lichens, a symbiotic organism of fungi and algae, cause serious damage to national heritages of stone master piece and costly trees for gardening. The present study was conducted to screen effective fungicides against lichen-forming fungi to control the biological agents deteriorating stone heritages and trees. Five commercial fungicides (Fenarimol EC, Etridiazole EC, Iminoctadinetriacetate SL, Difenoconazole+lminocatadinetriacetate ME and Difenoconazole+Azoxystrobin SC) were tested against the lichen-forming fungi (LFF) isolated from seven saxicolous (Caloplaca sp., Ramalina sp., Xanthoparmelia sp., and Xanthoria sp.,) or corticolous (Parmelia sp.,) lichen species. Preliminary screening test showed that no LFF could grow on the MY (malt-yeast extract) agar medium amended with the recommended concentrations of each fungicide. Further screening was conducted at 1%, 10% and 20% of the recommended concentrations of the fungicides. After 7 week incubation at $15^{\circ}C$ in the dark, Difenoconazole+Iminocatadinetriacetate ME and Difenoconazole+Azoxystrobin SC completely inhibited the fungal growth of all the tested LFF, even at 1% of the concentration. Two fungicides of Fenarimol EC and Iminoctadinetriacetate SL exhibited a moderate inhibition activity at the lower concentrations. Etridiazole EC was less effective in the fungal growth inhibition than the other four fungicides. The results suggested that lichens colonizing on precious stone heritages and trees can be eradicated by applying Difenoconazole+Iminocatadinetriacetate ME and Difenoconazole+Azoxystrobin SC even 1% of the recommended concentrations. Selected fungicide application at such a low concentration will facilitate the chemical use to prevent and preserve stone heritages from biological deterioration induced by lichens and the allied microbes.