• BMB Reports
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• 제37권6호
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• pp.684-690
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• 2004

Heparin lyase I was purified to homogeneity from Bacteroides stercoris HJ-15 isolated from human intestine, by a combination of DEAE-Sepharose, gel-filtration, hydroxyapatite, and CM-Sephadex C-50 column chromatography. This enzyme preferred heparin to heparan sulfate, but was inactive at cleaving acharan sulfate. The apparent molecular mass of heparin lyase I was estimated as 48,000 daltons by SDS-PAGE and its isoelectric point was determined as 9.0 by IEF. The purified enzyme required 500 mM NaCl in the reaction mixture for maximal activity and the optimal activity was obtained at pH 7.0 and $50^{\circ}C$. It was rather stable within the range of 25 to $50^{\circ}C$ but lost activity rapidly above $50^{\circ}C$. The enzyme was activated by $Co^{2+}$ or EDTA and stabilized by dithiothreitol. The kinetic constants, $K_m$ and $V_{max}$ for heparin were $1.3{\times}10^{-5}\;M$ and $8.8\;{\mu}mol/min{\cdot}mg$. The purified heparin lyase I was an eliminase that acted best on porcine intestinal heparin, and to a lesser extent on porcine intestinal mucosa heparan sulfate. It was inactive in the cleavage of N-desulfated heparin and acharan sulfate. In conclusion, heparin lyase I from Bacteroides stercoris was specific to heparin rather than heparan sulfate and its biochemical properties showed a substrate specificity similar to that of Flavobacterial heparin lyase I.

• Toxicological Research
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• 제31권1호
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• pp.17-23
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• 2015

Excessive manganese (Mn) in the brain promotes a variety of abnormal behaviors, including memory deficits, decreased motor skills and psychotic behavior resembling Parkinson's disease. Hereditary hemochromatosis (HH) is a prevalent genetic iron overload disorder worldwide. Dysfunction in HFE gene is the major cause of HH. Our previous study has demonstrated that olfactory Mn uptake is altered by HFE deficiency, suggesting that loss of HFE function could alter manganese-associated neurotoxicity. To test this hypothesis, Hfe-knockout ($Hfe^{-/-}$) and wild-type ($Hfe^{+/+}$) mice were intranasally-instilled with manganese chloride ($MnCl_2$ 5 mg/kg) or water daily for 3 weeks and examined for memory function. Olfactory Mn diminished both short-term recognition and spatial memory in $Hfe^{+/+}$ mice, as examined by novel object recognition task and Barnes maze test, respectively. Interestingly, $Hfe^{-/-}$ mice did not show impaired recognition memory caused by Mn exposure, suggesting a potential protective effect of Hfe deficiency against Mn-induced memory deficits. Since many of the neurotoxic effects of manganese are thought to result from increased oxidative stress, we quantified activities of anti-oxidant enzymes in the prefrontal cortex (PFC). Mn instillation decreased superoxide dismutase 1 (SOD1) activity in $Hfe^{+/+}$ mice, but not in $Hfe^{-/-}$ mice. In addition, Hfe deficiency up-regulated SOD1 and glutathione peroxidase activities. These results suggest a beneficial role of Hfe deficiency in attenuating Mn-induced oxidative stress in the PFC. Furthermore, Mn exposure reduced nicotinic acetylcholine receptor levels in the PFC, indicating that blunted acetylcholine signaling could contribute to impaired memory associated with intranasal manganese. Together, our model suggests that disrupted cholinergic system in the brain is involved in airborne Mn-induced memory deficits and loss of HFE function could in part prevent memory loss via a potential up-regulation of anti-oxidant enzymes in the PFC.

• The Korean Journal of Physiology and Pharmacology
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• 제3권5호
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• pp.513-519
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• 1999

Direct exposure of renal tubular brush-border membranes (BBM) to free cadmium (Cd) causes a reduction in phosphate (Pi) transport capacity. Biochemical mechanism of this reduction was investigated in the present study. Renal proximal tubular brush-border membrane vesicles (BBMV) were isolated from rabbit kidney outer cortex by Mg precipitation method. Vesicles were exposed to $50{\sim}200\;{\mu}M\;CdCl_2$ for 30 min, then the phosphate transporter activity was determined. The range of Cd concentration employed in this study was comparable to that of the unbound Cd documented in renal cortical tissues of Cd-exposed animals at the time of onset of renal dysfunction. The rate of sodium-dependent phosphate transport $(Na^+-Pi\;cotransport)$ by BBMV was determined by $^{32}P-Iabeled$ inorganic phosphate uptake, and the number of $Na^+-Pi$ cotransporters in the BBM was assessed by Pi-protectable $^{14}C-labeled$ phosphonoformic acid $([^{14}C]PFA)$ binding. The exposure of BBMV to Cd decreased the $Na^+-Pi$ cotransport activity in proportion to the Cd concentration in the preincubation medium, but it showed no apparent effect on the Pi-protectable PFA binding. These results indicate that an interaction of renal BBM with free Cd induces a reduction in $Na^+-Pi$ cotransport activity without altering the carrier density in the membrane. This, in turn, suggest that the suppression of phosphate transport capacity $(V_{max})$ observed in Cd-treated renal BBM is due to a reduction in $Na^+-Pi$ translocation by existing carriers, possibly by Cd-induced fall in membrane fluidity.

• 대한한방부인과학회지
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• 제18권4호
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• pp.72-84
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• 2005

Purpose : This study was carried out to investigate the relaxational response to the water extract of Sobokchukeo-Tang(SCT) in isolated uterine muscle in rats. Methods : Segments of uterine muscle obtained from female rats immediately after delivery were mounted in organ baths superfused on a polygraph. The effects of SCT on the tension of potassium induced contracture were studied in rat uterine smooth muscles. All experiments were performed in Krebs-Henseit solution which was aerated with 100% oxygen and kept at $37^{\circ}C$. Results : KCI did not produce contraction in calcium-free solution, but $CaCl_2$ induced concentration-dependent contraction after depolarizing with KCI. SCT inhibited the tonic contraction of uterine muscle as dose dependent manner. And when SCT was pretreated in calcium-free medium, it showed more powerful relaxational effect. The effect of 10mg/ml concentration of SCT was equal to that of 9nM and 70nM of nifedipine and verapamil and the relaxational effect of SCT on rat uterine muscle can be assumed to be concerned with the action of cyclic AMP. But the action mechanism of relaxation on the rat uterine muscles were concerned with the calcium channel. Conclusion : From this study we could suggest that the relaxtional effect of SCT on uterine muscle be available to preventing and curing dysmenorrhea.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 춘계학술발표회
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• pp.161-165
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• 2005

Recently, it is on the increase interest for Al alloy with new material for ship application to substitute for FRP ship. The reason is thatAl alloy ship has beneficial characteristics such as high sea speed, increase of loadage and easy to recycle compared with FRP ship. In this paper, mechanical and electrochemical properties are investigated by slow strain rate test experiment in various applied potential condition. These results will provide as reference data to design ship by deciding optimum protection potential regard to hydrogen embrittlement and stress corrosion cracking. In general, Al and Al alloys are not corroded with forming film which has the corrosion resistance property in neutral solution. However, it was observed that formation and destruction of passive film by $Cl^-$ ion in sea water environment. At comparison of current density after 1200 sec in potentiostatic experiment, the current density in the potential range of -0.68 $\~$-1.5 V is shown low value. The low current density means protection potential range. Elongation in applied potential of 0 V was high. However, the corrosion protection application in this condition is impossible potential because the toughness is low value by decreasing strength by active dissolution reaction at parallel part of specimen. The film composed with $CaCO_3$ and $Mg(OH)_2$ has a corrosion resistance property. However, the uniform electrodeposition coating at below -1.6 V potential is not formed since the time to form the uniform electrodeposition coating is short. Therefore, it is concluded that mechanical property is poor because effect by hydrogen gas generation is larger than that of electrodeposition coating. It is concluded that the optimum protection potential range from comparison of_maxim urn tensile strength, elongation and time to fracture is -1.3$\~$0.7 V (SSCE).

• The Korean Journal of Physiology
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• 제29권1호
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• pp.81-89
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• 1995

The effects of prolactin and vasopressin on the regulation of amniotic fluid (AF) volume and its $Na^{+}$ concentration $([Na^{+}])$ through the membrane surrounding the AF during increase in AF volume due to fetal urination were studied. About 70% of AF volume was replaced with normal isotonic saline solution. Isotonic saline solution (0.5 ml) containing Censored and LiCl was introduced into each amniotic sac. Vasopressin (25 ng/ml) or prolactin (1 mg/ml) of AF was then injected into experimental amniotic sac. The concentrations of Congored, $Li^{+}$, and $Na^{+}$ were measured at 30 and 60 min intervals after injection. Af samples with decreased Censored concentration ([CR]) during the period of 30 - 60 min were analyzed. The percentage change of $[Na^{+}]$ and the rate of $Li^{+}$ movement during this period were calculated, and the effects of vasopressin and prolactin on them were evaluated. Fellowing results were obtained: 1. The rate of reduction of [CR] in the AF was retarded by vasopressin or prolactin injection. 2. The rate of reduction of $[Li^{+}]$ in the AF was also retarded by vasopressin or prolactin injection. 3. The rate of reduction of $[Li^{+}]$ in the AF was less retarded by vasopressin than that of [CR]. 4. $[Na^{+}]$ changed to approach to the normal level, but this was markedly retarded by prolactin injection. 5. Direction of $Li^{+}$ movement was correlated with the change in $[Na^{+}]$ but it always moved out of the amniotic sac even when the $[Na^{+}]$ increased in vasopressin injected AF. From the above results, it is suggested that vasopressin in the AF triggers the fetus to urinate, and then the membranes surrounding the AF regulate osmolarity by efflux of $Na^{+}$. We suggest that prolactin facilitates water outflow across the amniotic membrane during increase in AF volume, in contrast to a constant volume, whereas regulation of $[Na^{+}]$ is partly restricted by prolactin.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.448-448
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• 2010

Magnetic random access memory (MRAM) has made a prominent progress in memory performance and has brought a bright prospect for the next generation nonvolatile memory technologies due to its excellent advantages. Dry etching process of magnetic thin films is one of the important issues for the magnetic devices such as magnetic tunneling junctions (MTJs) based MRAM. CoFeB is a well-known soft ferromagnetic material, of particular interest for magnetic tunnel junctions (MTJs) and other devices based on tunneling magneto-resistance (TMR), such as spin-transfer-torque MRAM. One particular example is the CoFeB - MgO - CoFeB system, which has already been integrated in MRAM. In all of these applications, knowledge of control over the etching properties of CoFeB is crucial. Recently, transferring the pattern by using milling is a commonly used, although the redeposition of back-sputtered etch products on the sidewalls and the low etch rate of this method are main disadvantages. So the other method which has reported about much higher etch rates of >$50{\AA}/s$ for magnetic multi-layer structures using $Cl_2$/Ar plasmas is proposed. However, the chlorinated etch residues on the sidewalls of the etched features tend to severely corrode the magnetic material. Besides avoiding corrosion, during etching facets format the sidewalls of the mask due to physical sputtering of the mask material. Therefore, in this work, magnetic material such as CoFeB was etched in an ICP etching system using the gases which can be expected to form volatile metallo-organic compounds. As the gases, carbon monoxide (CO) and ammonia ($NH_3$) were used as etching gases to form carbonyl volatiles, and the etched features of CoFeB thin films under by Ta masking material were observed with electron microscopy to confirm etched resolution. And the etch conditions such as bias power, gas combination flow, process pressure, and source power were varied to find out and control the properties of magnetic layer during the process.

• Journal of Plant Biotechnology
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• 제48권4호
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• pp.255-263
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• 2021

Paederia foetida L. is an important medicinal plant that has been used for the treatment of various gastrointestinal related ailments by different tribal communities in India. This plant is also known for its use as a food. Due to overexploitation, P. foetida has been classified as a vulnerable plant in some states of India. The propagation of P. foetida by conventional methods is easy but very slow. Synthetic seed technology offers incredible potential for in vitro propagation of threatened and commercially valuable plants, and can also facilitate the storage and exchange of axenic plant material between laboratories. However, synthetic seed production for P. foetida has not yet been reported. Thus, to the best of our knowledge, the present study is the first attempt to produce synthetic seeds of P. foetida by calcium alginate encapsulation of in vitro regenerated axenic nodal segments. Sodium alginate (3%) and CaCl₂ (100 mM) were found to be the optimal materials for the preparation of ideal synthetic seeds, both in terms of morphology and germination ability. The synthetic seeds showed the best germination (formation of both shoot as well as root; 83.3%) on ½ MS medium augmented with 0.5 mg/L indole-3-acetic acid. The plantlets obtained from these synthetic seeds could be successfully acclimatized under field conditions. We also studied the storage of these synthetic seeds at low temperature and their subsequent sprouting/germination. The seeds showed a germination rate of 63.3% even after 21 days of storage at 4 ℃; thus, they could be useful for transfer and exchange of P. foetida germplasm.

• 대한본초학회지
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• 제36권1호
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• pp.1-8
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• 2021

Objective : Citri Unshius Pericarpium (Citrus unshiu peel) has been used in Korean medicine to treat indigestion, vomiting, coughing and phlegm. This study investigated the hepatoprotective effect of ethanol extract of Citrus unshiu peel (CEE) in cadmium (CdCl2)-treated mouse model. Methods : CEE was dissolved in water and administered orally to mice once a day for 7 consecutive days. The mice were then exposed to a single intraperitoneal (i.p.) injection of cadmium (4 mg/kg body weight) to induce acute hepatotoxicity. At the end of the experiment, blood and liver tissue samples were collected, analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), and histopathological evaluation. Liver damage was assessed as the percentage of degenerative areas of the hepatic parenchyma, the number of degenerative hepatocytes, and the number of infiltrated inflammatory cells. Results : In cadmium-treated rats, pretreatment with CEE significantly reduced the serum ALT and AST levels associated with liver damage. Histopathologically, CEE prevented degenerative changes on the hepatic tissues including confluent necrosis, congestions and infiltration of inflammatory cells. CEE also reduced the elevation of oxidative stress markers (nitrotyrosine and 4-hydroxynonenal) and apoptosis markers (cleaved caspase-3 and cleaved PARP) positive cells. PARP protein expression in liver tissue was also restored by CEE. Conclusion : This study showed that CEE exerted antioxidant and anti-apoptotic effects against cadmium-induced liver injury. Thus, it can be concluded that CEE can be used to prevent liver damage caused by cadmium.

• 미생물학회지
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• 제36권2호
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• pp.91-96
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• 2000

불와전 균류인 Fusarium s^g pp.를 이용하여 여러 가지 배양조건과 생리적 영향에 따른 균주의 성장 및 T-2 toxin의 생성에 관하여 고찰하였다. T-2 toxin 의 검출방법은 thin layer chromatography (TCL) 법과 미생물학적 검출방법을 사용하였다. 고체 배지의 경우 횐옥수수 가루(Quaker사 제품)베지에서 다른 곡물보다 많은 양의 T-2 toxin이 생성되었으며,비교적 깨끗한 T-2 toxin이 정제되었다. 이 경우 배지 100g당 약 700 mg의 T-2 toxin이 생성되었으며, 그중 약 30%정도가 깨끗한 결정으로 정제되었다. 고온(20-$25^{\circ}C$)에서는 생장은 많았으나, T-2 toxin의 생성은 적었으며, 저온(10-$15^{\circ}C$)에서는 비교적 생장이 적었지만, T-2 toxin의 생성이 많았고, 젖당, 글리세롤, 솔비톨의 경우는 적었다. 유일 탄소원으로 구연산과 초산은 이용하지 못하였으며, 녹발의 경우 생장은 많았으나 T-2 toxin의 생성양은 적었다. 질소원의 경우 $NaNO_2$를 제외하고는 $(NH_4)_2NO_4$, $NH_4Cl_3$, $NH_4NO_3$, $KNO_3$ 를 거의 동일하게 이용하였다. 초기 pH값에 생성과 균주의 성장은 pH4.0-5.0일 경우 최적을 나타냈으며 ph6.0이상에서는 성장도 저하되고, T-2 toxin생성도 적었다. 회전속도에 따른 T-2 toxin 생성과 균주의 성장을 보면 회전속도가 속돠 증가함에 따라 균주의 생장과 T-2 toxin 생성량이 모두 증가하였다. $15^{\circ}C$에서 7일간 배양 후, $25^{\circ}C$로 옮겨 7일간 배양하여, toxin의 생성을 보면, $15^{\circ}C$에 7일간 배양했을 때보다 T-2 toxin양이 적었다. 이는 생성되었던 T-2 toxin이 분해되었음을 보여주는 것이다. 이상의 결과를 볼 때 T-2 toxin 대사 경로는 온도에 의한 효소 억제 또는 효소 유지 시스템에 의해 조절되는 것이라고 생각할 수 있다.