• Korean Journal of Microbiology
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• v.25 no.4
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• pp.274-281
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• 1987

The effects of bovine serum albumin, myoinositol and ergosterol on protoplast formation, regeneration and fusion from auxotrophic mutants of Candida pseudotropicalis were examined. Frequency of protoplast formation ranged from 48 to 98% depending on auxotrophic types. When myoinositol (0.5mg/ml) and ergosterol (0.1mg/ml) were supplemented in the medium of cell growth, and bovine serum albumin (4mg/ml)was added to protoplasting buffer, 50-100% of cells were converted to protoplasts. Such a treatment of three additives improved 2.2-3.0 fold of regeneration rate of protoplasts. The fusion frequencies between complementary auxotrophs ranged from $7.0\times 10^{-4}$ to $1.5\times 10^{-3}$ in the optimal conditions. These values showed 1.9-2.3 fold increase when compared with fusion frequencies obtained without the treatment of additives. These results suggested that these comsion frequencies obtained without the treatment of additives. These results suggested that these xompounds may improve protoplast regeneration and fusion between complementary auxotrophs used in this study.

• Korean Journal of Agricultural Science
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• v.34 no.1
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• pp.13-18
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• 2007

This study was carried out to investigate the effects of ovarian estrus stage of oocytes and supplementation of medium with BSA, cysteine and myoinositol on in vitro maturation of canine oocytes. The in vitro maturation(IVM) rate to metaphase II (M II) stage of oocytes recovered from different stage of the reproductive cycle (inactive, follicular and luteal stage) cultured in TCM-199 media were $0.0{\pm}0.0%$, $10.0{\pm}4.1%$ and $5.7{\pm}1.6%$, respectively. The IVM rate of oocytes collected from follicular stage was significantly higher in inactive or luteal stage of oocytes. The IVM rates of oocytes recovered from different stage of the reproductive cycle cultured in TCM-199 media with 5% BSA and 0.1 mM cysteine were$0.0{\pm}0.0%$, $15.8{\pm}4.7%$, $5.6{\pm}1.5%$, respectively. The IVM rates of oocytes recovered from different stage of the reproductive cycle cultured in TCM-199 media with 5% BSA and 10 mM myoinositol were $0.0{\pm}0.0%$, $18.4{\pm}4.6%$ and $5.7{\pm}1.9%$, respectively. The IVM rate of follicular stage oocytes was significantly higher in oocytes collected from follicular stage and with cultured 5% BSA and 0.1 mM cysteine or 5% BSA and 10 mM myoinositol compared to other experimental group.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.243-250
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• 1986

Protoplast formation and regeneration from wild-type and auxotrophic mutants of Candida pseudotropicalis CBS 607 as well as fusion between complementary mutants were carried out. Frequencies of protoplast formation from wild-type and histidine or adenine requiring mutants ranged from 96 to 100% whereas those from methionine or tryptophan auxotrophs were 52 and 72%, respectively. When bovine serum albumin(4mg/ml, BSA) was added to protoplasting buffer for cells of methionine or tryptophan auxotrophs grown in a medium supplemented with myoinositol(0.5mg/ml), 96-99 % of cells were converted to protoplasts. Protoplasts were regenerated at the frequencies ranging from 18 to 20%. However, the addition of BSA to protoplasting buffer and the supplement of myoinositol to a medium of cell growth doubled the regeneration rate except adenine auxotroph in which such an improvement was not observed. It was found that optimal concentrations of polyethylene glycol and $CaCl_2$ are 20% and 100mM while optimal pH and exposure time are 6.0 and 30min. The fusion frequencies between complementary mutants ranged from $1.5{\times}10^{-3}\;to\;8.8{\times}10^{-3}$ and were enhanced by the improvement in the rate of protoplast regeneration. When histidine auxotroph was fused with tryptophan mutant, several fusion products were obtained which were found to be in the state of aneuploid or diploid, judging from DNA content and the presence of a large nucleus in the products.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.183-183
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• 2005

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.327-332
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• 2000

Supended cells of Camptotheca acuminata were observed to lose their ability to synthesize camptothecin and its derivatives as a result of repeated cultures. Accordingly, the maintenance of high-yield cells by cryopreservation was sudied to overcome this stability problem, and various factors involved were optimized. Pregrowing the cells in 8% myoinositol for 4 days was found to be the most effective in improving survival. The highest survival was obtained when the pregrown cells were cryoprotected with a mixture of 10% DMSO, 0.6M mannitol, and 10% glycerol. When the cryopreserved cells were maintained in a freezer at $-70^{\circ}C$, 94% survival was obtained after 4 months. The survivals after 5 and 8 months of storage decreased to 52% and 45%, respectively. No loss of biosynthetic capacility of camptothecin was observed after short to medium term cryopreservation of C. acuminata.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.188-196
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• 1988

Intergeneric or intraspecific protoplast fusion between Saccharomyces cerevisiae X-2180-1A, Candida pseudotropicalis ATCC 8619 and CBS 607 was attempted to produce ethanol from lactose containing materials. Teh intergeneric fusion frequency between Saccharomyces cerevisiae X-2180-1A (ade rho) and Candida pseudotropicalis CBS 607 (his met) was $1.0\times 10^{-5}$. These values exhibited approximately 2-3.5 fold increase when compared with fusion frequency obtained without the treatment of bovine serum albumin, myoinositol and ergosterol, suggesting that these compounds may improve intergeneric of intraspecific protoplast fusion. Nuclear fusion appears to occur in fusants between intergenera(S. cerevisiae+C. pseudotropicalis) and intraspecies (C. pseudotropicalis strains) as strongly suggested by DNA content, nuclear staining, comparison of survival rate to UV light and isolation of recombinants after mitotic segragation. It was also found that alcohol production from intraspecific hybrids was somewhat increased when compared with that from their parents.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.460-465
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• 1990

Regeneration of protoplast was effective by preincubating spore suspension containing 30$\mu g$/ml of 2-DG for 4 hours, and CBE medium containing casamino acid, bovine serum albumin, ergosterol and myoinositol was found to be more efficient than any other regeneration medium tested in this experiment. The regeneration frequency was about 30%. Optimal conditions for conidial protoplast fusion were obtained by treatment of protoplasts with 10 mM $CaCl_2$ and 30% polyethylene glycol 4000 (pH 7.5) as fusogenic agent at $37^{\circ}C$ for 10 minutes. The fusion frequency was $8.2\times 10^{-4}$. The higher productivity of enzyme of fusant FWN-56 was achived: 2.3-fold for CMCase, 1.5-fold for avicelase, 1.8-fold for $\beta$-glucosidase and 2.5-fold for xylanase compared to that obtained in two parental strains. The genetic stability of fusant after maintenance on minimal medium for more than 4 weeks was high because segregant rate was below 1%. The conidial DNA content of fusant was 1.4-1.6 times higher than that of the parental strains, The nucleus size of fusants were also higher than that of each parental strains.

• Progress in Medical Physics
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• v.28 no.4
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• pp.135-143
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• 2017

Chemical Exchange Saturation Transfer (CEST) imaging is a method to detect solutes based on the chemical exchange of mobile protons with water. The solute protons exchange with three different patterns, which are fast, slow, and intermediate rates. The CEST contrast can be obtained from the exchangeable protons, which are hydroxyl protons, amine protons, and amide protons. The CEST MR imaging is useful to evaluate tumors, strokes, and other diseases. The purpose of this study is to review the mathematical model for CEST imaging and for measurement of the chemical exchange rate, and to measure the chemical exchange rate using a 3T MRI system on several amino acids. We reviewed the mathematical models for the proton exchange. Several physical models are proposed to demonstrate a two-pool, three-pool, and four-pool models. The CEST signals are also evaluated by taking account of the exchange rate, pH and the saturation efficiency. Although researchers have used most commonly in the calculation of CEST asymmetry, a quantitative analysis is also developed by using Lorentzian fitting. The chemical exchange rate was measured in the phantoms made of asparagine (Asn), glutamate (Glu), ${\gamma}-aminobutyric$ acid (GABA), glycine (Gly), and myoinositol (MI). The experiment was performed at a 3T human MRI system with three different acidity conditions (pH 5.6, 6.2, and 7.4) at a concentration of 50 mM. To identify the chemical exchange rate, the "lsqcurvefit" built-in function in MATLAB was used to fit the pseudo-first exchange rate model. The pseudo-first exchange rate of Asn and Gly was increased with decreasing acidity. In the case of GABA, the largest result was observed at pH 6.2. For Glu, the results at pH 5.6 and 6.2 did not show a significant difference, and the results at pH 7.4 were almost zero. For MI, there was no significant difference at pH 5.6 or 7.4, however, the results at pH 6.2 were smaller than at the other pH values. For the experiment at 3T, we were only able to apply 1 s as the maximum saturation duration due to the limitations of the MRI system. The measurement of the chemical exchange rate was limited in a clinical 3T MRI system because of a hardware limitation.

• Progress in Medical Physics
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• v.29 no.1
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• pp.29-41
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• 2018

The objective of this study was to evaluate the chemical exchange saturation transfer (CEST) effect of amino acids and neurotransmitters, which exist in the human brain, depending on the concentration, pH, and amplitude of the saturation radiofrequency field. Phantoms were developed with asparagine (Asn), ${\gamma}-aminobutyric$ acid (GABA), glutamate (Glu), glycine (Gly), and myoinositol (MI). Each chemical had three different concentrations of 10, 30, and 50 mM and three different pH values of 5.6, 6.2, and 7.4. Full Z-spectrum CEST images for each phantom were acquired with a continuous-wave radiofrequency (RF) saturation pulse with two different $B_1$ amplitudes of $2{\mu}T$ and $4{\mu}T$ using an animal 9.4T MRI system. A voxel-based CEST asymmetry was mapped to evaluate exchangeable protons based on amide (-NH), amine ($-NH_2$), and hydroxyl (-OH) groups for the five target molecules. For all target molecules, the CEST effect was increased with increasing concentration and B1 amplitude; however, the CEST effect with varying pH displayed a different trend depending on the characteristics of the molecule. On CEST asymmetric maps, Glu and MI were well visualized around 3.0 and 0.9 ppm, respectively, and were well separated macroscopically at a pH of 7.4. The exchange rates of Asn, Glu, BABA, and Gly usually decreased with increasing pH. The CEST effect was dependent on the concentration, acidity of the target molecules, and B1 amplitude of the saturation RF pulse. The CEST effect for Asn can be observed in a 9.4T MRI system. The results of this study are based on applying the CEST technique in patients with neurodegenerative diseases when proteins in the brain are increased with disease progression.

• Journal of Mushroom
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• v.9 no.3
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• pp.123-131
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• 2011

Winter mushroom was monitored to investigate the influence of storage temperature on its quality during the storage and distribution phase. In measuring its quality, the contents of saccharides were quantified with its fruiting bodies using HPLC. Although it has been known to be difficult to separate saccharide isomers, our results indicated that Grace Prevail carbohydrate ES $5{\mu}column$ was the best in the separation to analyze the saccharide out of six columns used in this study. In our results, xylose was the main component of saccharide in the fruiting body of winter mushroom(White line mushroom:47.68mg/g, brown line mushroom: 63.28mg/g). In long-term storage, the total amount of saccharide tended to increase, but trehalose content of the disaccharide decreased. In comparison with the paramount amount of lactose and myo-inositol contents in long-term storage at $4^{\circ}C$, lactose wasn't detected when stored at $-1^{\circ}C$.