• Korean Journal of Microbiology
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• v.24 no.4
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• pp.364-369
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• 1986

A procedure for the preparation, regeneration and fusion of protoplasts of Streptomyces tubercidicus was confirmed. Also, protoplast releasingprocesses from mycelia were observed by scanning electron microscope. Three types of protoplasts releasing processes-from the hyphal tip, hyphal end regions and lateral regions of the hyphae-were observed. More than 17% regeneration efficiency was obtained by regeneration medium that is composed of tryptone-yeast extract-sodium acetate-$MgCl_2-CaCl_2$-sucrose. Optimal concentrations of $Ca^{++},\;Mg^{++}$ and sucrose in the regeneration medium were 50mM, 0.4-0.5M respectively. Above 30% of fusion frequency of the protoplasts derived from two auxotrophic strains of S. tubercidicus was induced by polyethylene glycol 4000(60% w/v).

• BMB Reports
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• v.31 no.6
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• pp.600-603
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• 1998

A highly thermostable xylose isomerase from Thermus thermophilus has been expressed in Escherichia coli and crystallized. The purified enzyme shows its optimum temperature at $90^{\circ}C$. It has been crystallized at room temperature using polyethylene glycol 4000 as the precipitant. The crystal belongs to the orthorhombic space group $P2_12_12_1$, with unit cell parameters of a = 73.34 ${\AA}$, b = 144.05 ${\AA}$, c = 155.07 ${\AA}$. The presence of one molecule of tetrameric xylose isomerase in the asymmetric unit gives a crystal volume per protein mass ($V_m$) of 2.32 ${\AA}^3/Da$ and the solvent content of 47.0% by volume. The diffraction pattern extends to 1.9 ${\AA}$ Bragg spacing with synchrotron radiation and a set of native data has been collected to 2.3 ${\AA}$.

• Mycobiology
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• v.29 no.1
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• pp.15-18
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• 2001

Protoplast fusion is a useful technique for establishing fungal hybrids to overcome the natural barriers. The ultrastructure of protoplast and its fusion process were observed using a scanning electron microscopy(SEM) and a transmission electron microscopy(TEM). The protoplasts were variable in size from $0.5{\sim}15{\mu}m$ in diameter, and the mean diameter was about $3{\sim}5{\mu}m$. It was impossible to discriminate protoplasts of Lentinula edodes from protoplasts of Coriolus versicolor by size and surface structure. Big aggregates of the dehydrated protoplasts were observed, after polyethylene glycol 4000 treatment. Nucleus, mitochondria, lipid granules and various vesicles having granules were scattered in the cytoplasm. The vesicles were heterogeneous in size and vary from one protoplast to another. The fused membrane layer of the two protoplasts was observed. Time protoplast membrane contact and reorganization of membrane components were essential condition for protoplast fusion. Transmission electron micrograph showed fused protoplasts and flattening of the cells in the area of the membrane contact. We hope that our electron microscopic observations provide some insights into the understanding of the fusion process of protoplast in fungi.

• Journal of Pharmaceutical Investigation
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• v.16 no.1
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• pp.1-7
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• 1986

The influences of sodium chloride, polyethylene glycol 4000 and 20000 on 5-fluorouracil release from disk type silicone polymer devices were examined in isotonic phosphate buffer. These water soluble cosolvent and sodium chloride caused devices to swell in aqueous media. Sodium chloride exerted the greatest influence on drug release. The addition of water soluble cosolvent or sodium chloride to silicone polymeric devices permitted controlled release of 5-fluorouracil, presumably due to the change of the physical microstructure of silicone network, and the solubility and diffusivity of 5-fluorouracil. It seemed that the water soluble drug was released through the hydrophilic pores or pathways formed in the device by the incorporation of a water soluble cosolvent or sodium chloride.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.2
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• pp.127-133
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• 2023

Purpose: Dyssynergic defecation (DSD) is one of the important causes of chronic constipation in children. We aimed to analyze the clinical features, diagnostic test results, and treatments for DSD in children. Methods: Children diagnosed with DSD using fluoroscopic defecography were enrolled in this study. Clinical data, including the results of colon transit time (CTT) test and biofeedback (BF) therapy, were collected from medical records retrospectively. Results: Nineteen children were enrolled. The median age was 9 years (6-18 years), the median frequency of bowel movement was 1/7 days (1-10 days), the median duration of constipation was 7.0 years (2-18 years), the median age of onset of constipation was 2.5 years (1-11 years). In the CTT test, outlet obstruction type was noted in 10/18 (55.6%), slow transit type in 5/18 (27.8%), and normal transit in 1/18 (5.6%). The median CTT was 52 hours (40-142 hours). Initial medical therapy was performed with the polyethylene glycol 4000, and the response was good in 9/19 (47.4%), fair in 9/19 (47.4%), and poor in 1/19 (5.0%). BF was performed in 8/19, with good results in 6/8 (75.0%) children and failure in 2/8 (25.0%) children. After long-term medical therapy (11/19), 3/5 showed good response with medication alone, 6/8 showed good response with BF and medication combined. Conclusion: DSD should be considered as a cause of chronic constipation in children, especially in those with abnormal CTT test results. BF combined with medical therapy is effective even with age-limited cooperation.

• The Korean Journal of Food And Nutrition
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• v.19 no.4
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• pp.358-365
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• 2006

To study simultaneous water and solute transport kinetics during soaking in concentrated solution, the influence of the concentration and molecular weight of the solute(polyethylene glycol(PEG) and NaCl) in the soaking solution and the temperature on the water loss and solute gain rates were observed by using a model vegetable tissue(potato). When potato slices$(4cm{\times}4cm{\times}0.1cm)$ soaked in 60% PEG solutions, the water loss rate of the early phase decreased with increasing of the molecular weight of PEG from 200 to 6,000, while the final water loss increased with increasing the molecular weight of PEG and it reached to 80%. The cell wall of potato tissue was permeable to NaCl and PEGs of which average molecular weight is smaller than 400 but it was not permeable to PEG 600 and larger molecules. PEG which has average molecular weight below 600 induced plasmolysis and those above 600 induced cytorrhysis. The water loss rate of potato sample soaked in smaller molecular weight PEG solution was faster than those soaked in higher molecular weight PEG solution before cytorrhysis happened. The water loss rate was reversed after cytorrhysis happened. The volume change of potato within the first 60 minutes was larger in low molecular PEG solution but the final ratio of decreasing volume was larger in high molecular PEG solutions. In PEG 200 solution, the potato tissue was slightly shrinked without shape change. However, in PEG 4,000 solution, volume of potato was reduced significantly and potato tissue was twisted.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.384-389
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• 1992

Bacillus sp. YBL-7 which had been isolated from ginseng root-rot suppressive soil was able to antagonize Fusarium solani causing ginseng root-rot by their antibiotic substance. In order to develop multifunctional antagonist on Bacillus sp. YBL-7 as a biocontrol agent against Fusarium salam', optimal conditions for protoplast transformation system of Bacillus sp.YBL-7 by the vector plasmid pE194 were investigated. The protoplasts of Bacillus sp. YBL-7 were obtained at best efficiency by treatment with 200${\mu}g$/ml of lysozyme in the pH 7.0 of SMM buffer for 90 minutes at $40^{\circ}C$. The cell wall of the protoplast was regenerated on the agar plate containing 1.2% agar and 0.7 M mannitol. Under the best condition for protoplast formation and regeneration, the optimal transformation was achieved with 40% polyethylene glycol (M.W. 4000) treatment for 10minutes. The vector plasmid pE194 showed the best transformation frequency at 5$\mu$g/ml of final concentration. The pE194 was very stable over 80% in the transformants.

• Journal of Conservation Science
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• v.36 no.3
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• pp.225-235
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• 2020

The present study aimed to monitor changes in the amount of PEG free-flowing back from PEG-treated woods and compressive strength changes with change in relative humidity from 90% to 30%. The change in the relative humidity was done 3 times. For the current study, water-logged wood (Prinus group) was used and the wooden blocks cut out of it were subjected to 3 different impregnation methods combined with different drying conditions as follows: 1) impregnating with 80% PEG#4000 followed by drying in nature (hereafter PEG80), 2) impregnating with 40% PEG#4000 and then drying in vacuum freeze drying equipment (hereafter PEG40), and 3) impregnating with 40% PEG#4000 in t-butanol, followed by drying in the vacuum freeze drying equipment (hereafter TB40). It was verified that most of the PEG was free-flowing back from the PEG-treated woods; however, a small amount of left PEG was observed on the lumen surface. The amount of PEG free-flowing back from the PEG-treated woods increased whenever the relative humidity changes from 90% to 30%. The compressive strengths of PEG80 and TB40 were increased whenever the relative humidity changed from 90% to 30%, whereas PEG40 decreased. The current study showed how to control the relative humidity to effectively manage PEG-treated waterlogged woods.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.356-361
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• 1991

- To investigate the possibility of genetic development for a multi-purpose strain of Bacillus subtilis YBL-7 against Fusat-iurn solani causing root rot of many impotant corps, the plasmid pGU66 inserting urease gene of Bacillus pasteurii had been introduced into Bacillus subtilis YBL-7 by PEG-induced protoplast (PIP) transformation system. Protoplasts of B. subtilis YBL-7 were prepared by treating the cells with lysozyme (200 $\mu g$/ml) in hypertonic buffer (SMMP). The highest transformation frequency was achieved when cells of the strain with lysozyme at $42^{\circ}C$ for 90 minutes. Optimal transformation was obtained using polyethylene glycol (MW 4000) at final concentration of 30% (V/V). The transformation frequency was increased proportionally to 1.2 $\mu g$ of plasmid DNA. At best condition, the transformation frequency (transformants/ regenerants/$\mu g$ of DNA) for pGU66 was appoximately $4 \times 10^{-3}$. Also, the urease gene was strongly expressed in the transformants of B. subtilis YBL-7 and maintained steadily. The antifungal ability of transformant was very similar to that of B. ssubtilis YBL-7.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.88-93
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• 1989

To improve a new yeast strain capable of converting xylan to ethanol directly, we tried protoplast fusion between xylose fermenting yeast (Candida sp. X-6-41) and xylan assimilating yeast (Crypto-coccus sp. XB-33), finally selected the most promising two fusants (XFU-1 and XFU-2). As the optimum conditions for protoplast formation, the yeast cells were cultured to exponential phase in YPD and YPX containing 0.6M KCI, respectively, and then treated with zymolyase (0.25mg/$m\ell$), cellulase(4mg/$m\ell$) and 100mM 2-mercaptoethanol at pH 8 and 3$0^{\circ}C$. The protoplasts of parental auxotrophs were fused in the presence of 20mM CaCl$_2$and 40% polyethylene glycol(M.W.4000). The physiological and morphological characteristics of the fusants, such as assimilation of carbon sources, cell size, growth rate, xylanase activity and xylan fermentation ability were investigated. Xylanase activity of fusants that cultured in chemically minimal medium was higher than that of fusants that cultured in completed medium, because xylanase producing activity of xylose fermenting yeast(X-6-41) was inhibited by isoleucine.