• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.71-74
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• 1999

The crude enzyme prepared from the culture supernantant of Arthrobacter sp. S37 was purified by Phenyl Toyopearl column chromatography. Six endo-inulinases were detected by activity staining on native PAGE and named Inu I to Inu VI. Endo-inulinase were further purified by DEAE cellulose column chromatography and band slicing. Inu II~VI produced mainly inulotriose (F3) and inulotetraose (F4) as well as a small amount of inulobiose (F2) and fructose in contrast to Inu I producing F3, F4 and F5 from inulin. The N-terminal amino acid sequence of native and six CNBr-cleaved fragment of Inu VI were determined. No homology was found in amino acid sequences between Inu VI and other fructan hydrolase including invertase reported.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.733-738
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• 2007

An extracellular exoinulinase($2,1-\beta-D$ fructan fructanohydrolase, EC 3.2.1.7), which catalyzes the hydrolysis of inulin into fructose and glucose, was purified 23.5-fold by ethanol precipitation, followed by Sephadex G-100 gel permeation from a cell-free extract of Kluyveromyces marxianus YS-1. The partially purified enzyme exhibited considerable activity between pH 5 to 6, with an optimum pH of 5.5, while it remained stable(100%) for 3 h at the optimum temperature of $50^{\circ}C$. $Mn^{2+}\;and\;Ca^{2+}$ produced a 2A-fold and 1.2-fold enhancement in enzyme activity, whereas $Hg^{2+}\;and\;Ag^{2+}$ completely inhibited the inulinase. A preparation of the partially purified enzyme effectively hydrolyzed inulin, sucrose, and raffinose, yet no activity was found with starch, lactose, and maltose. The enzyme preparation was then successfully used to hydrolyze pure inulin and raw inulin from Asparagus racemosus for the preparation of a high-fructose syrup. In a batch system, the exoinulinase hydrolyzed 84.8% of the pure inulin and 86.7% of the raw Asparagus racemosus inulin, where fructose represented 43.6mg/ml and 41.3mg/ml, respectively.

• Applied Biological Chemistry
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• v.35 no.3
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• pp.202-209
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• 1992

In order to study on the viscous substance produced during Chungkookjang fermentation, one strain which produce a lot of viscous substance was isolated from the rice straw and identified as Bacillus sp; This strain produced the most viscous substance in 48 hours at $42^{\circ}C$, in splite of little change of amino type nitrogen and ammonia type nitrogen when added M.S.G., while the yield of viscous substance and amino type nitrogen was increased but that of ammonia type nitrogen was decreased when added susrose. Molecular weight of viscous substance estimated between 15,000 and 65,000. Viscous substance was confirmed mostly composed of glutamate and fructose by G.C. and HPLC analysis. Composition of viscous substance would be controlled according to the changes of media.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2990-2996
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• 2009

S. mutans, one of a major causal agents of dental caries, is component of the dental plaque and produces various organic acids such as lactic acid as the end-product of glycolysis. In this study, we are interested in comparing the gene expression of acid-shocked and control cells of S. mutans isolated from Korean with caries. Expression levels of gtfB, gtfC, gtfD and ftf were analyzed by Real-time PCR, when the cells were grown under 20 mM lactic acid stress in the exponential phase. The data showed reduced expression of these genes. S. mutans is known to have developed a variety of mechanisms to tolerate acid sterss. A more detailed analysis of the functions and interactions of acid stress proteins connecting the growth, stress tolerance, biofilm formation is under way.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.1
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• pp.57-64
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• 2005

월동기간 동안 zoysiagrass[Zoysia matrella(L.) Merr]와 creeping bentgrass(Agrostis palustris Hunds)의 저온 스트레스에 대한 탄수화물 대사 반응을 구명하기 위해 11월부터 이듬해 4월까지의 식물체내의 탄수화물 대사산물의 변화를 비교 분석하였다. Creeping bentgrass의 녹색도와 뿌리 성장은 온도변화와 거의 평행하게 변화하였으나 zoysiagrass는 뿌리 성장에 거의 변화가 없이 3월 말까지 담황색을 나타냈다. 11월부터 이듬해 1월까지 zoysiagrass에서 glucose와 sucrose 함량은 크게 높았고, 1월에서 4월까지 starch를 제외한 모든 탄수화물 화합물들의 감소의 정도가 현저하게 낮았다. Reeping bentgrass에서 fructan의 depolymerization이 2월 이후 단당류와 이당류의 감소와 일치했으나 zoysiagrass에서는 starch 가수분해가 11월부터 일찍이 시작되었다. 이상의 결과들은 creeping bentgrass와 비교 했을때 zoysisagrass 뿌리의 높은 비구조적 탄수화물의 농도가 저온 내성과 밀접한 관계가 있음을 잘 나타내어 주고 있다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.81-88
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• 2001

To investigate C and N metabolisms in response to potassium-deficient stress during regrowth of Italian ryegrass(Lolium multiflorum L.), C and N metabolites were analyzed at day 0 (cutting date), 6, 12 and 24 days after defoliation. K-sufficient (control, +K) and K-absent (-K) nutrition solutions were applied from 7 days before defoliation, and continued for one cycle of 24 days-regrowth period. During 24 days of regrowth dry matter of regrowing shoots and remaining tissues were not significantly different between +K and -K treatment. In remaining stubble, all C compounds in both +K and -K treatment largely decreased (69% to 84% of the initial level) during the first 6 days of regrowth, and then rapidly recovered. The decline of soluble sugars and fructan in roots for the first 6 days much less in the -K medium. Amino acids, soluble and insoluble proteins in stubble also feel down during the first 6 days, thereafter actively replenished in both +K and -K treatment. The decline of nitrate in stubble prolonged to 12 days of regrowth. Initial amounts of all N compounds in roots were significantly lower in the -K medium. Higher accumulation of amino acids and soluble protein in roots in the -K medium was observed after 12 days of regrowth. In regrowing shoots, 3 all carbohydrates increased with a very similar pattern for both treatments. Nitrate was not significantly different between two treatments. Depress of soluble protein accumulation in -K medium was noteworthy after 12 days of regrowth. These results indicated that an active utilization of organic reserves occurred to support regrowth even under K deficient condition with a similar extent with K sufficient condition.

• Applied Biological Chemistry
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• v.39 no.3
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• pp.165-171
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• 1996

The rheological properties of biopolymers produced by Bacillus sp. K-1 and its mutant strains(KM-21, KM-83) were studied. Apparent viscosity of biopolymers decreased as rising the temperature. The biopolymer produced by KM-21 strain showed 1.7 times low viscosity, 2.7 times low viscosity by K-1 and 1.9 times low viscosity by KM-83 at $80^{\circ}C$ compared with at $20^{\circ}C$ respectively. The viscosity of biopolymer solution also increased with increasing the polymer concentration and showed pseudoplastic characteristics which is high temperature dependency in all concentration. The change of the biopolymer viscosity on the pH showed the highest value at the pH 7.0 and it showed lower at acidic condition than at alkaline condition comparatively.

• Journal of Life Science
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• v.19 no.9
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• pp.1218-1225
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• 2009

Difractose anhydrides (DFAs) is studied as a sweetener for diabetics because of its structural property. DFAs have four types: DFA I, III, IV (degradation of levan) and V (degradation of inulin). Especially, DFA IV has been shown to enhance the absorption of calcium in experiments using rats. Levan fructotransferase is an enzyme for producing di-d-fructose-2,6':6,2-dianhydride (DFA IV). To identify structural characterization, we purified wild-type and mutants (D63A, D195N and N85S) of levan fructotransferase (LFTase) from Microbacterium sp. AL-210. These proteins were purified to apparent homogeneity by Ni-NTA affinity column, Q-sepharose ion exchange and gel filtration chromatography and detected by SDS-PAGE. They were also analyzed by circular dichroism (CD) measurements, JNET secondary structure prediction, activity measurements at various temperatures, and pH analysis. The optimum pH for the enzyme-catalyzed reaction was pH 7.5 and optimum temperature was observed at $55^{\circ}C$. Along with wild-type LFTase, mutants were analyzed by CD measurement, fluorescence analysis and differential scanning calorimetry (DSC). N85S showed less $\alpha$-helix and more $\beta$ strand than others. Also, N85S showed almost the same curve as wild-type in their steady-state fluorescence spectra, whereas mutant D63A and D195N showed higher intensity than wild-type. The amino acid sequence of wild-type LFTase was compared to the sequences of exo-inulinase from Aspergillus awamori, a plant fructan 1-exohydrolase from Cichorium intybus, and Thermotogo maritime (Tm) invertase and showed a high identity with Exo-inulinase from Aspergillus awamori.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.4
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• pp.267-276
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• 2006

To investigate the physiological responses to winter freezing stress naturally occurring, the level of lipid peroxidation and enzymatic antioxidant responses were compared between zoysiagrass and creeping bentgrass during overwintering. Root mortality of creeping bentgrass was significantly higher than zoysiagrass at January. Root growth of creeping bentgrass was nearly parallel with temperature fluctuation, while zoysiagrass showed little changes in root growth until the end of April. Total nonstructural carbohydrate of zoysiauass was 10% higher than creeping bentgrass. Malondialdehyde(MDA) content in creeping bentgrass was 2-fold higher than that of zoysiagrass. The peroxidase(POD) activity of creeping bentgrass in January was 4.2 times higher, while superoxide(SOD) and catalase(CAT) activities lowered 22% and 67%, respectively, compared to zoysiagrass. These results suggest that zoysiagrass roots much properly operate cold tolerance mechanism and: are less susceptible to cold stress in comparison to creeping bentgrass.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.250-258
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• 1989

S. mutans known as a causative causative agent of dental caries was isolated from a carious lesion of Korean in the present study. The physiological, biochemical characteristics and polysaccharide pattern of these isolates were compated with those of four laboratory strains ; AHT(a), FA-1F(b), LM7(e), and OMZ65(g). One hundred strains of oral streptococci were isolated from dental caries sites of Korean (one male and one female). Among these, 3 strains were identified as S. mutans. These strains were able to grow on selective media MS, MST, MSP, MSP1, MSB, MSBT and were stained dark pink when sprayed with solutions of mannitol and TTC. So, these strains were called strain 108, 110, and 120, respectively. Strain 108, 110, and 120 were bacitracin resistnt. As these strains contained particularly hippurate hydrolysis enzyme, they were distinguished from laboratory strains. Apart from laboratory strains, the strain 108 was not capable of fermenting lactose, the strain 110 was not able to ferment sorbitol, inulin, melibiose, raffinose and the strain120 was incapable of fermenting inulin, raffinose. All fractions of extracellular and ecll bound polysaccharide of the strain108, 110, and 120 were consisted of more glucan than fructan. Aside from laboratory strains, the isolated strains were composed of more water-insoluble glucans related adherence on solid surface than water-soluble. According to these results, the strain108, 110, and 120 had native characteristecs of S. mutans, but they were different from laboratory strains in some characteristics. Therefore, each of them was given a name to S. mutans KHC108, KHC110, and KHC120, respcetively.