• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.19-23
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• 2001

Physicochemical properties including viscosity, temperature and pH stability, color turbidity and moisture retention power of xylooligosaccharide(XO) as food material were investigated to apply to food process. The viscosity of 70 bx XO was 930 cP at $20^{\circ}C$ and 90 cP at $60^{\circ}C$, which was higher than that of sugar but lower than that of other oligosacchrides. XO remained stable after heat treatment for 1hr at $100^{\circ}C$ and pH 2.5 to 8.0 indicating excellent heat and pH stability. The pH of XO was measured $5.0{\pm}0.1$ and the color turbidvity of XO was very low at pH $2.5{\sim}4.0$. The color turbidity of XO increased as pH increased, but it was not high enough to affect food process. When heated with 1% glycine the color turbidity of XO was very low and changed little with pH changes. To measure moisture retention power XO was stored at $25^{\circ}C$ and 75% relative humidity for 71 day. XO retained more than 95% of the original weight; whereas sugar lost 28%. These results suggest that XO has useful physicochemical properties for various food process to improve the functionality of food.

• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.679-685
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• 2011

Xanthomonas oryzae pv. oryzae (Xoo) produces a putative effector, XoAvrBs2. We expressed XoAvrBs2 homologously in Xoo with a TAP-tag at the C-terminus to enable quantitative analysis of protein expression and secretion. Addition of rice leaf extracts from both Xoo-sensitive and Xoo-resistant rice cultivars to the Xoo cells induced expression of the XoAvrBs2 gene at the transcriptional and translational levels, and also stimulated a remarkable amount of XoAvrBs2 secretion into the medium. In a T3SS-defective Xoo mutant strain, secretion of the TAPtagged XoAvrBs2 was blocked. Thus, we elucidated the transcriptional and translational expressions of the XoAvrBs2 gene in Xoo was induced in vitro by the interaction with rice and the induced secretion of XoAvrBs2 was T3SSdependent. It is the first report to measure the homologous expression and secretion of XoAvrBs2 in vitro by rice leaf extract. Our system for the quantitative analysis of effector protein expression and secretion could be generally used for the study of host-pathogen interactions.

• Journal of Nutrition and Health
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• v.53 no.4
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• pp.390-405
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• 2020

Purpose: The effect of prebiotics intake after administration of a synbiotics mixture (a probiotic, Bifidobacterium longum, and a prebiotic, xylooligosaccharide containing sugar [XOS]) on human intestinal microflora and defecation characteristics was investigated in a randomized controlled trial. Methods: Twenty-five healthy young volunteers (11 males and 14 females) were randomly assigned to 2 groups (BL2XO2 and BL2XO6). The synbiotics mixture was orally administered to both groups for 2 weeks, and the prebiotics were subsequently administered to the BL2XO6 group for 4 additional weeks. The daily dose of the synbiotics mixture comprised 10¹⁰ colony-forming unit of Bifidobacterium longum and 10 g of XOS, and during the prebiotics period, the daily dose of prebiotics comprised only 10 g of XOS. The fecal pH, microflora, and defecation characteristics were analyzed at baseline and at weeks 1, 2, 4, and 6. Results: The counts of B. longum and Bifidobacterium spp. in the BL2XO6 group exhibited a steady, increasing trend during the synbiotics and prebiotics periods, whereas those of the BL2XO2 group exhibited considerable variation in each week of the study period. Although there was no significant difference, the counts of fecal Bifidobacterium in the BL2XO6 group tended to be higher than those of the BL2XO2 group at week 6. The growth of Lactobacillus spp. exhibited a time-dependent variation, peaking at week 6 in both groups. Low counts of Clostridium spp. were observed after treatment with the synbiotics and prebiotics in the BL2XO6 group (p < 0.05) throughout the study, whereas the inhibitory effect on Clostridium spp. was maintained only during the synbiotics period in the BL2XO2 group. The defecation characteristics did not differ between the two groups. Conclusion: Administration of XOS after a synbiotics mixture containing B. longum and XOS can exert a prebiotic effect in healthy young volunteers by stimulating Bifidobacteriun spp. growth and inhibiting growth of Clostridium spp.

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.311-316
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• 1978

The reaction between iron(III) and Xylenol Orange (XO or $H_6A$) has been investigated spectrophotometrically. It has been established that iron (III) and XO form two complexes with compositions iron(III) : XO = 2 : 1 and 1 : 1. The 2 : 1 complex is stable in acidic medium containing excess of iron, and 1 : 1 complex is stable in slightly acidic medium containing excess of XO. The absorption maxima are at 590 nm (2 : 1) and 500 nm (1 : 1), the molar absorptivities being $3.18{\pm}0.04{\times}10^4,\;1.32{\pm}0.03{\times}10^4$respectively. The stability constants of two complexes studied by varying pH are $loglog{\beta}_{21}=18.69{\pm}0.03,\;log{\beta}_{212}=42.08{\pm}0.09,\;log{\beta}_{11}=4.17{\pm}0.04,\;and\;log{\beta}_{113}=34.47{\pm}0.07.$

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.42.2-42.2
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• 2018

고전적인 소행성과 혜성의 경계는 무너지고 있다. 처음 발견했을 때는 소행성으로 분류됐던 천체도, 예기치 않은 활동성이 나타나면 혜성의 일원이 된다. 소행성은 충돌이나 회전가속에 의해 갑자기 활동성을 나타내기도 하지만, 강한 태양복사를 견디지 못하고 오랜 시간 간직해온 휘발성 물질을 우주 공간으로 흩뿌리기도 한다. 한국천문연구원 딥사우스 (DEEP-South) 팀은, 이렇게 태양 근방에서 혜성으로 탈바꿈할 것으로 예상되는 소행성으로 2000 XO8을 지목하고, 근일점을 막 지난 2017년 10월 말부터 KMTNet 망원경으로 약 한 달간 지속 관측을 하였다. 이 기간 동안 2000 XO8은 활동성이 급격히 증가하여 선명한 꼬리를 나타냈고, 이내 검출 한계 이하로 활동성이 줄어드는 것까지 확인하였다. 이번에 혜성으로 밝혀진 2000 XO8은 한국인 또는 한국 기관에서 새로 발견 및 동정한 것으로 알려진 혜성 중에 그 주기가 8.8년으로 가장 짧다. 이는 궤도장반경이 목성보다 안쪽에 위치한다는 점에서 이례적인 일이다. 우리는 궤도 실험을 통해 2000 XO8이 현 궤도에 자리 잡은 지 오래 되지 않았으며, 또 다른 주기 혜성 265P/LINEAR에서 쪼개져 나온 조각일 가능성을 제시하고자 한다.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1614-1620
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• 2015

Plasmid-cured derivative strains of Bacillus anthracis are frequently used in laboratory studies. Plasmid incompatibility, which does not increase the risk of chromosomal mutation, is a useful method for plasmid curing. However, in bacteria containing multiple plasmids, it often requires the sequential introduction of multiple, specific incompatibility plasmids. This lengthy process renders the traditional plasmid incompatibility method inefficient and mutation-prone. In this study, we successfully cured plasmids pXO1 and pXO2 from B. anthracis A16 simultaneously using only one recombinant incompatible plasmid, pKORT, to obtain a plasmid-free strain, designated A16DD. This method may also be useful for the simultaneous, one-step curing of multiple plasmids from other bacteria, including Bacillus thuringiensis and Yersinia pestis.

• Applied Microscopy
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• v.31 no.3
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• pp.275-285
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• 2001

The pulmonary alveolar macrophage is thought to play an important role in the mediation of acute inflammatory lung injury by secretory products including degraded enzymes, cytokines, and reactive oxygen metabolites . This study was conceived to understand the role of alveolar macrophage in oxidative stress induced acute lung injury. To examine the alveolar macrophages and xanthine oxidase (XO) activity in bronchoalveolar lavage fluid (BALF), time-dependent changes of numbers of alveolar macrophages, monocytes and neutrophils in alveolar cavity were counted in association with ultrastructural and cytochemical observations of lung tissue and alveolar cells. The number of monocytes was increased (p<0.001) at 1h after IL-1 treatment compared with that of sham. At 2h after instillation of IL-1, the number of alveolar macrophages was the highest, XO activity in BALF was elevated at 2h after IL-1 instillation and the activity was markedly elevated(p<0.05) at 3h after IL-1 treatment. On the basis of these experimental results, it is suggested that, during early phase of acute lung injury induced by IL-1, alveolar macrophage-derived XO contributes to lung injury earlier than the neutrophilic respiratory burst.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.369-377
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• 2013

In order to increase the utilization of sweet potato leaves and stalks as much as roots, it is necessary to study their beneficial potential. In this study, the antioxidant, antiallergic and anti-inflammatory effects of sweet potato leaves and stalks were evaluated by measuring total polyphenol and flavonoid contents, DPPH radical scavenging effects, the reducing power and inhibition effects on xanthine oxidase (XO), 5-lipoxygenase (LOX), and cyclo-oxygenase (COX)-2 activities. Blanched sweet potato leaves (SL), raw whole purple stalks (ST) and peeled stalks (PST) were freeze-dried and extracted with 95% ethanol. Total polyphenol content was highest in SL (11.03 mg/g), followed by ST (0.87 mg/g), and PST (0.37 mg/g). Total flavonoid content was highest for SL (9.01 mg/g), followed by ST (0.50 mg/g) and PST (0.25 mg/g). The $IC_{50}$ for DPPH radical scavenging effects was highest for SL ($43.6{\mu}g/mL$), followed by ST ($308.4{\mu}g/mL$) and PST ($1,631.3{\mu}g/mL$). The reducing power was highest for SL ($59.72{\mu}g$ ascorbic acid eq./mL), followed by ST ($12.56{\mu}g$ ascorbic acid eq./mL) and PST ($2.18{\mu}g$ ascorbic acid eq./mL) with $1,000{\mu}g/mL$ of ethanol extract. The inhibition rate on XO activity was highest for SL (13.06%), followed by ST (5.05%) and PST (0.0%) at $250{\mu}g/mL$ extract treatment. The inhibition rate on COX-2 activity was highest for SL (55.34%), followed by ST (2.18%) and PST (0.0%) at $250{\mu}g/mL$ extract treatment. The inhibition rate on 5-LOX activity was highest for SL (91.16%), followed by ST (33.38%) and PST (14.93%) at $50{\mu}g/mL$ treatment. Taken together, sweet potato leaves showed high antioxidative, anti-allergic and anti-inflammatory activities, especially with very strong inhibition effects on 5-LOX activity. These beneficial effects of sweet potato leaves might be mainly caused by the high content of polyphenols and flavonoids.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11a
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• pp.194-204
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• 1999

The use of genetically cloned xylanase acquired from Bacillus strearthermophillus improves bleachability for oak kraft pulps. Combination of xylanase(X). oxygen(O), ozone(Z). peroxide(P), alkaline extraction(Eo. Eop), and chlorination(C/D, D) have been tested in a variety of bleaching sequences. The effectiveness of xylanase pre-treatment(XO) and post-treatment(OX) in oxygen bleaching is mainly compared. With xylanase treatment the brightness increase by 1.5-2.1% ISO in OZEP, OZEoP, OZEopP and OPZP sequences. There is only numerically difference of brightness gains between OX and XO sequences. With xylanase treatment chemical requirements for bleaching decrease by 42.6-48.6% in OC/DEoD sequence and 47.9-54.7% as active chlorine in OC/DEopD sequence at the same brightness. the reduction of bleaching chemicals is higher in XO sequence than those in OX sequence. Following xylanase treatment the viscosity increases from 11.7-12.0 mPa·s to 12.4-13.5 mPa·s and the brightness stability is considerably improved however the difference of effectiveness between XO and OX sequence is not present. Compared to tensile index vs tear index, the physical properties are similar for TCF bleaching sequences with and without xylanase treatments. However in OC/DEoD and OC/DEopD sequences the physical properties decrease with xylanase treatment. There is no difference in the physical properties between XO and OX sequences. COD, BOD and color of bleaching effluents increase slightly with xylanase treatment, however the discharge of COD end-load into environmental impact decrease.

• Analytical Science and Technology
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• v.7 no.3
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• pp.277-284
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• 1994

The spectrophotometric determination of rare earth elements with XO was investigated in the presence of cetylpyridium chloride(CPC), dodecyltrimethylammonium bromide(DTMAB), cetyltrimetylammonium bromide (CTMAB), Triton X-100 at pH 6.2. The complex between XO and rare earth elements in the presence of cationic surfactants was very stable and more sensitive than in the absence of surfactants. The largest absorbance increase was provided by CTMAB, which was therefore chosen for determination of rare earth elements. REE-XO-CTMAB complex has absorption maxima at 618nm and obeys the Beer's law in the range of 0~0.5 ppm. Molar absorptivity was $1.5{\times}10^5mol^{-1}cm^{-1}l$.