• KSBB Journal
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• v.16 no.4
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• pp.409-414
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• 2001

Biosynthesis of curdlan( ${\beta}$-1,3 glucan) was shown by fluorscence on cellufluor medium. The highest production of curdlan was produced when glucose was used as a carbon source and ($NH_4$)$_2$$SO_4$ was used as a nitrogen source. ${\beta}$ -form of curdlan was detected in the fingerprint region (890 $cm^{-1}$) by FT-IR spectrum and shown homogeneous ${\beta}$ -1,3 glucan by $^{13}C$ NMR spectrum ($C_1$-103 ppm, $C_2$-73.2 ppm, $C_3$-86.4 ppm, $C_4$-68.7 ppm, $C^{5}$-76.63 ppm, $C_{6}$-61.2 ppm). Transition of structure from triple helix coil form to random coil form was appeared at 0.1 ∼0.25 M NaOH concentration. It was shown that natural curdlan is a triple helix form in neutral but becomes weak in alkaline condition.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.546-551
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• 2005

[ ${\beta}-1,3-Glucan$ ] (curdlan) is a water-insoluble polysaccharide composed exclusively of ${\beta}-1,3\;linked$ glucose residues. Extracellular curdlan was mostly synthesized by Agrobacterium species and Alcaligenes faecalis under nitrogen-limiting conditions. In this study, we screened the microorganisms capable of producing extracellular curdlan from soil samples. For the first time, we reported Gram-positive bacterium Bacillus sp. SNC 107 capable of producing extracellular curdlan in appreciable amounts. The effect of different carbon sources on curdlan production was studied and found that the yield of curdlan was more when glucose was used as carbon source. It was also found that maximum production was achieved when the initial concentration of ammonium and phosphate in the medium was 0.5 and 1.9 g/L respectively. In this study the curdlan production was increased from 3 to 7g/L in shake flask cultures.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.674-679
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• 2005

With addition of uracil during fermentation, the production rate of $1,3-{\beta}-glucan(curdlan)$ was enhanced. Since uracil was used as precursor of UDP-Glucose, the UDP-glucose level was increased and further glucan synthesis rate was increased.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.668-671
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• 2005

In this study, the full gene of the putative ${\beta}-1,3-glucan$ synthase catalytic subunit(gi:40556679) in Agrobacteriujm sp. ATCC31750 was cloned into E. coli BL21(DE). We found that putative ${\beta}-1,3-glucan$ synthase catalytic subunit full gene mutant(E. coli mutant FC) produced soluble glucan.instead of curdlan(insoluble glucan).

• KSBB Journal
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• v.19 no.5
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• pp.406-409
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• 2004

Matrix Assisted Laser Desorption ionization Time of Flight (MALDI-TOF) was used for enzymes identification related to B -1,3-glucan synthesis. Agrobacterium sp. ATCC31750 was cultivated with two stage Continuous Stirrer Tank Reactor (CSTR) and the cells were harvested and their protein profiles were analysed by two dimensional electrophoresis. The specific enzyme spot was treated with trypsin and ana lysed by MALDI-TOF to get peptide molecular weight. The peptide molecular weights were matched with Agrobacterium tumefacience's Data Base from the matrix science site, then could identify the avaliable key enzymes. In this study, we identified key metabolite of synthesis of beta-1,3-glucan, such as glucose-6-phosphate isomerase, phosphoglucomutase, B-1,3-glucan synthase and glucokinase, and we also identified uracil phosphoribocyl transferase and Ribosome recycling factor also.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.200-204
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• 2000

Protein conjugation of curdlan belonging to $\beta$-1, 3-glucan was carried out to improve it surface functionalities. The glucan was mixed with phosvitin, {TEX}$$\alpha$_{s}${/TEX}-casein, lysozyme or ovalbumin, respectively. The mixture was freeze-dried, and he resulting powder was incubated at 6$0^{\circ}C$ and 79% relative humidity for 12 days in order to generate a controlled Maillard reaction between curdlan and proteins. conjugation with unfolding proteins, i.e., phosvitin and {TEX}$$\alpha$_{s}${/TEX}-casein, drastically increased the solubility of the glucan, whereas lysozyme and ovalbmin did not. The solubility in water of curdlan was 3.44% for the phosvitin conjugate and 1.09% for the {TEX}$$\alpha$_{s}${/TEX}-casein conjugate. SDS-slab polyacrylamide gel electrophoresis showed that curdlan was solubilized due to covalent binding with phosvitin. Emulsifying properties of curdlan were substantially improved by the conjugation with phosvitin and {TEX}$$\alpha$_{s}${/TEX}-casein. Emulsion stability of the curdlan-phosvitin conjugate was about 2.9 times greater than that of the curdlan-phosvitin mixture.

• Archives of Pharmacal Research
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• v.24 no.2
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• pp.109-113
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• 2001

Curdlan is a natural $\beta$-1,3-glucan produced by Agrobacterium biovar 1. In this study, the anticoagulant activity of sulfoalkyl derivatives of curdlan was investigated by carrying out activated partial thromboplastin time (APTT) assay and compared with that of o-sulfonated curdlan. Approximately 100-fold higher concentration of o-sulfonated curdlan than heparin was required to obtain the same level of the clotting time. Anticoagulant activity of curdlan derivatives was dependent on the degree of sulfation in prolonging the clotting time. However, the chain length of the substituent did not play a role in prolonging the clotting time. The curdlan derivatives enhanced thrombin inhibition by mediating through antithrombin III. The inhibition of thrombin by o-sulfonated curdlan was found to be approximately 10-fold weaker than that by heparin.

• IMMUNE NETWORK
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• v.4 no.2
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• pp.94-99
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• 2004

Background: We previously reported that ginsan, a polysaccharide extracted from Panax ginseng had an immunostimulatory activity such as mitogenic activity, activation of macrophages and killer cells, and production of a variety of cytokines which resulted in antitumor and antiseptic effects. We further purified $\alpha$-(1$\longrightarrow$6)-glucan and $\beta$-(2$\longrightarrow$6)-fructan from the ginsan with size exclusion and ion-exchange column chromatography successively. In this study, we performed the structure-based activity of ginsan by comparison with known polysacchrides such as $\beta$-glucan, curdlan, laminarin, levan, dextran, lentinan and OK-432. Methods: To investigate the immunostimulatory activity of several polysaccharide compounds, we investigated the stimulation of lymphocytes proliferation, the generation of activated killer cells and the secretion of nitrites from activated macrophages. Results: Of polysaccharides tested, curdlan and ginsan stimulated lymphocyte proliferation, suggesting that the molecular weight and composition of polysaccharide are dependent on the mitogenic activity. The production of nitric oxide was significantly increased in curdlan, levan, ginsan and its fraction, indicating that fructan has also capacity to activate macrophages and may devote to kill pathogens. In addition, the activation of macrophages was seemed to be independent of molecular weight of polysaccharide. The generation of AK cells was exhibited in order of curdlan, OK-432> F1, ginsan, F3> levan> etc. The AK activity may be dependent on molecular weight and composition of polysaccharides. Conclusion: Unfortunately, purified polysaccharide from ginsan were less active on immunostimulatory activity than mixed compounds of polysaccharides. From the viewpoint of structure and activity relationships, we found several characteristic features.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.46-49
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• 2005

Curdlan, a natural $\beta-1,3-glucan,$ has been studied as drug carrier due to its unique properties including its thermal gelling characters. In this study, curdlan was chemically acetylated for pH-sensitive drug delivery. Curdlan acetate microspheres(CAMs) were prepared by the solvent evaporation method. The size of the CAMs was below $200{\mu}m.$ The drug loading efficiency of microspheres was approximately $58.44\%$. In the swelling test, the CAMs showed pH-sensitive behavior. The swelling capacity of microspheres at pH 7.4 was much greater than at pH 1.4. Also, release rate of indomethacin(IND) at pH 7.4 from the CAMs was faster than that at pH 1.4. Therefore the CAMs have potential for the controlled release of IND over an extended period of time.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.663-667
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• 2005

Water-soluble glucan was produced by mutants of E. coli BL21(DE)/CrdS-F and E. coli BL21(DE)/CrdS-C in a fermentor. Mutants of E. coli BL21(DE)/CrdS-F which has putative ${\beta}-1,3-glucan$ synthase catalytic subunit (gi:40556679) gene and E. coli BL21(DE)/CrdS-C which contains the active catalytic domain of partial curdlan synthase gene. The molecular weight of water-soluble glucan was analysed with HPLC.