• Korean Journal of Microbiology
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• v.20 no.3
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• pp.125-133
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• 1982

Mutational experiments were performed to imporve the cellulase productivity of Aspergillus phoenicis KU175, isolated from the southern part of Korea, as a high cellulase producer. By treatment ultra-violet light nad 4-NQO(4-Nitroquinoline-N-Oxide), mutation waas induced, and treatment ultra-violet light and 4-NQO (4-Nitroquinoline-N-Oxide), mutation was induced, and A.phoenicis KU175-115 was finally selected for its highest avicelase production. Avicelase production of the mutant was increased about 2 times compared with those of the wild strain. However, activities of other hydrolytic enzymes, such as amylase, protease and nuclease, of the mutant strain didn't show a marked difference compared with those of the nuclease, of the mutant strain didn't show a marked difference compared with the wild strain, except slight increase in ribonuclease activity and slight decrease in glucoamylase activity. Avicelases from the mutant strain selected were purified from wheat bran culture by successive salting out, followed by dialysis and column chromatography, and their charcteristics were compared with thosw of the wild strain. Avicelase was separated into three peaks in the mutant strain as well as in the case of wild strain. Avicelase II activity of the mutant strain was prominently higher than that of the wild strain, while avicelase I and III activities of those were equivalent. The optimal pH ranges and stability of avicelase II from the mutant strain were pH4-5 and pH3.5-6.0, respectively, as well as in the case of the wild strain. The optimal temperature and thermal stability of avicelase II from the mutant strain were $40{\sim}50^{\circ}C\;and\;20{\sim}55^{\circ}C$, respectively. These results were same as those of the wild strain. By the using of Eadie-Hofastee plot, $K_m\;and\;V_{max}$ of avicelase II from the mutant and the wild strain were calculated to be 2.29mg/ml and $4.84{\mu}g$ reducing sugar as glucose per min equally, from the line fitted to the data by the least square method. Activity of avicelase II from the mutant strain was slightly activated by $Mg^{++}\;but\;inhibited\;by\;Cu^{++}, \;Mn^{++}\;and\;Zn^{++}$, as well as in the case of the wild strain. Therefore, it was concluded that the mutant didn't induce the formation of another avicelase isozyme, or the changes in the properties of avicelase, but induce the changes in the productively of the same avicelase II by the action of regulatory gane.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.3
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• pp.274-279
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• 1985

Proximate compositions, minerals and protein fractions of the roots of cultured and wild Codonopsis lanceolata of different age groups were examined as the basic research for the study of their source of processed foods. The most abundant proximate composition of the roots of C. lanceolata was observed to be total sugars and next come crude protein, crude fiber, crude fat and ash in descending order irrespective of cultured and wild ones. The richest mineral contained in the roots was noticed to be K and followed by Mg and Ca. Generally increased tendency of crude protein, fat, ash, K, Mg, Ca, Mn, Zn, Cu and P contents were observed with older roots, however, decreased total sugars and Fe content. Lead and cadmium content was far bellow the authorized tolerance limits. The quantitative fractionation of the protein of the roots ranked albumin the highest content, followed by globuin, prolamin and glutelin. Decreased albumin content was observed with the older age roots, while increased globulin, prolamin and glutelin content. The minimum solubility of the soluble protein of the roots was found to be at pH 4.0 and maximum, at pH 10.0. Disc gel electrophoresis of the soluble protein of C. lanceolata roots showed almost similar patterns and numbers of bands. The molecular weight for main band protein was estimated to be about 90,000.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1469-1473
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• 2011

The efficacy of antimicrobial agents and heat treatments on spore inactivation was investigated. Grapefruit seed extract (GFE) and ethylenediaminetetraacetic acid (EDTA) were used and as antimicrobial agents, and heat treatments were conducted at $70^{\circ}C$, $80^{\circ}C$, and $90^{\circ}C$ for 30 minutes. Heat treatments at $90^{\circ}C$ were the most effective on spore inactivation as a single treatment and caused a 2.3 log reduction. When combined with a single treatment to discover synergistic effects, 1% GFE with $80^{\circ}C$ heat treatments and 0.5 mM EDTA with $80^{\circ}C$ heat treatments resulted in 2.1 log and 3.2 log reductions, respectively, though they did not show reductions at each single treatment (GFE 1% (v/v), EDTA 0.5 mM, $80^{\circ}C$). So it was concluded that by combining GFE, EDTA in low concentration treatment, and heat treatment, B. cereus spores can be effectively inactivated.

• Journal of Nutrition and Health
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• v.34 no.1
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• pp.14-22
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• 2001

In this study, we examined the effects of dietary fatty acids and vitamin E supplementation on antioxidant systems in the rat brain regions. The Sprague Dawley rats were fed the experimental diets 3-4 wks prior to the conception. Experimental diet consisted of 10% fat(wt/wt) which were safflower oil(SO, poor in $\omega$3 fatty acids), mixed oil(MO, P/M/S ratio=1.03:1.45:1,$\omega$6/$\omega$3 ratio=6.3) and mixed oil supplemented with vitamin E(ME:MO+500mg vitamin E/kg diet). At 3 and 9 weeks of age of the newborn rats, frontal cortex(FC), corpus striatum(CS), hippocampus(H) cerebellum(CB) were dissected out from the whole brain. Activities of glutathione peroxidase(GSH-P(sub)x, superoxide dismutase(SOD) concentrations of malondialdehyde(MDA) were mesaured. Dietary fatty acids were not effective in antioxidative system for rat brain. However, when vitamin E was supplemented to the diet(ME), the activities of GSH-P(suh)x tended to increase in comparison to MO group. Therefore, the activites of GSH-P(suh)x of FC and H at the age of 3 weeks showed significant differences(p<0.05). The activities of Total-SOD tended to decrease in ME group compared to MO group. There were significant differences(p<0.05) in FC and CS at the age of 3 weeks. The activities of Mn-SOD tended to increase and Cu, Zn-SOD tended to decrease when vitamin E was supplemented. The activity levels of antioxidative enzymes at the age of 3 weeks and 9 weeks were similar. This suggested that the activity level of antioxidative enzymes reached to the adult level at the age of 3 weeks which is the end point of lactation period. The concentrations of MDA were not altered by experimental diets. When the activities of antioxidant enzymes were compared, the activities of antioxidant enzymes were the lowest in H and FC. In conclusion, the antioxidative system were not altered by dietary fatty acid at the age of 3 weeks and 9 weeks, but the supplementation of vitamin E altered the antioxidative systems. Therefore, these findings should be considered comprehensively in scope of the balance of various antioxidative systems and their interactions(Korean J Nutrition 34(1):14-22, 2001)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.11
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• pp.707-711
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• 2014

The $0.99Bi_{0.5}(Na_{0.78}K_{0.22})_{0.5}TiO_3-0.01LaAlO_3$, $0.01LaMnO_3$ or $0.01LaFeO_3$ (0.99BNKT-0.01LA, 0.01LM or 0.01LF) ceramics were prepared by a conventional mixed mothod. The structure and morphology of the lead free ceramics were characterized by XRD (X-ray diffraction) and FE-SEM (field emission scanning electron microscopy). XRD results indicated that the BNKT ceramics modified by LA, LM or LF induced a transition from a ferroelectric tetragonal to a non-polar pseudo-cubic phase, leading to decrease in the remnant polarization ($P_r$) and coercive field ($E_c$) in the P-E hysterisis loops. The effects of the BNKT ceramics modified by La-based $ABO_3$ pervskite structure on the electric-field induced strain were investigated, and the largest normalized unipolar strain ($S_{max}/E_{max}$) was found in BNKT-0.01LF ceramic.

• Toxicological Research
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• v.17
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• pp.47-57
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• 2001

Alzheimer's disease (AD) is the most common cause of dementia in the elderly, and its pathology is characterized by the presence of numerous numbers of senile plaques and neurofibrillary tangles. Several genetic and transgenic studies have indicated that excess amount of $\beta$-amyloid protein (A$\beta$) is produced by mutations of $\beta$TEX>$\beta$-amyloid precursor protein and causes learning impairment. Moreover, $A\beta$ has a toxic effect on cultured nerve cells. To prepare AD model animals, we have examined continuous (2 weeks) infusion of $A\beta$ into the cerebral ventricle of rats. Continuous infusion of $A\beta$ induces learning impairment in water maze and passive avoidance tasks, and decreases choline acetyltransferase activity in the frontal cortex and hippocampus. Immunohistochemical analysis revealed diffuse depositions of $A\beta$ in the cerebral cortex and hippocampus around the ventricle. Furthermore, the nicotine-evoked release of acetylcholine and dopamine in the frontal cortex/hippocampus and striatum, respectively, is decreased in the $A\beta$-infused group. Perfusion of nicotine (50 $\mu\textrm{M}$) reduced the amplitude of electrically evoked population spikes in the CA1 pyramidal cells of the control group, but not in those of the $A\beta$-infused group, suggesting the impairment of nicotinic signaling in the $A\beta$-infused group. In fact, Kd, but not Bmax, values for ［$^3H$］ cytisine binding in the hippocampus significantly increased in the $A\beta$-infused rats. suggesting the decrease in affinity of nicotinic acetylcholine receptors. Long-term potentiation (LTP) induced by tetanic stimulations in CA1 pyramidal cells, which is thought to be an essential mechanism underlying learning and memory, was readily observed in the control group, whereas it was impaired in the $A\beta$-infused group. Taken together, these results suggest that $A\beta$ infusion impairs the signal transduction mechanisms via nicotinic acetylcholine receptors. This dysfunction may be responsible, at least in part, for the impairment of LTP induction and may lead to learning and memory impairment. We also found the reduction of glutathione- and Mn-superoxide dismutase-like immunoreactivity in the brains of $A\beta$-infused rats. Administration of antioxidants or nootropics alleviated learning and memory impairment induced by $A\beta$ infusion. We believe that investigation of currently available transgenic and non-transgenic animal models for AD will help to clarify the pathogenic mechanisms and allow assessment of new therapeutic strategies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.287-291
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• 1988

These studies were carried out to find out the polishing properties and cooking quality of the cut-polished barley. Naked barley, Youngsanbori which was produced in Chonnam province, Korea in 1981, was applied for this experiment. Polished barley was produced by the conventional method and cut-barley was manufactured by the method established by Wheat and Barley Research Institute. The yield of cut-polished barley was 68.2% and that of conventionally polished barley was 70.1 %. The ratio of length to width was 2.88 in cut-polished barley and that of conventionally polished barley was 1.36. And weight of 1,000 kernel was 9.5g in cut-polished barley and 18.5g in conventionally polished barley. Energy consumption was found to be 91.1kW/1,000kg in conventionally polished barley and 105kW/1,000kg in cut-polished barley. Whiteness, water uptake ratio and expanded volume of cooked barley were 45.5, 225.7 and 283% in conventionally polished barley and 49.5, 312.7 and 318% in cut-polished barley, respectively.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.230-237
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• 2004

In this study nitroreductase from Pseudomonas sp. HK-6 capable of degrading 2,4,6-trinitrotoluene (TNT) was characterized. Through a series of purification process including ammonium sulfate precipitation, DEAE-sepharose, and Q-sepharose, three different fractions I, II, and III having the enzyme activity of NTRs whose molecular weights were approximately 27 kDa were detected in fractions from HK-6 cells. Specific activity of the three fractions were approximately 4.85 unit/mg, 5.47 unit/mg, and 5.01 unit/mg, and concentrated to 9.0-, 10.1-, and 9.3-fold compared to crude extract, respectively. The optimal pH and temperature for the three NTR fractions were approximately 7.5 and $30^{\circ}C$, respectively. Metal ions, $Ag^{＋}$ , $Cu^{ 2+}$, $Hg^{2＋}$ inhibited approximately 70% of enzymes activities of all NTR, while $Fe^{2＋}$ did not stimulate or inhibit the activities. Monitoring the effect of chemicals on the enzyme activity revealed that those NTR fractions lost enzyme activity in presence of $\beta$-mercaptoethanol, but were a little influenced by dithiothreitol, EDTA and NaCl. The three NTR fractions demonstrated enzyme activities for nitrobenzene and RDX as well as TNT.

• The Korean Journal of Physiology
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• v.26 no.2
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• pp.113-122
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• 1992

It is well known that chromaffin cells of adrenal medulla secrete catecholamine in response to sympathetic nerve activation and the influx of $Ca^{2+}$ through the voltage dependent $Ca^{2+}$ channels (VDCC) in the cell membrane do a major role in this secretory process. In this study, we explored the effect of divalent cations on VDCC of rat chromaffin cells. Rat (Sprague-Dawley rat, 150-250 gm) chromaffin cells were isolated and cultured. Standard giga seal, whole cell recording techniques were employed to study $Ca^{2+}$ current with external and internal solutions that could effectively isolate VDCC currents $(NMG\;in\;external\;and\;TEA\;and\;Cs^{2+}\;in\;internal\;solution)$. The voltage dependence and the inactivation time course of VDCC in our cells were identical to those of bovine chromaffin cells. A persistent inward current was first activated by depolarizing step pulse from the holding potential (H.P.) of -80 mV to -40 mV, increased to maximum amplitude at around +10 mV, and became smaller with progressively higher depolarizing pulses to reverse at around +60 mV. The inactivation time constant $(\tau)$, fitted from the long duration test potential (2 sec) was $1295.2{\pm}126.8$ msec $(n=20,\;1\;day\;of\;culture,\;mean\;{\pm}S.E.M.)$ and the kinetic parameters were not altered along the culture duration. Nicardipine $(10\;{\mu}M)$ blocked the current almost completely. Among treated divalent cations such as $Cd^{2+},\;Co^{2+},\;Ni^{2+},\;Zn^{2+}\;and\;,Mn^{2+},\;Cd^{2+}$ was the most potent blocker on VDCC. When the depolarizing step pulse from -80 mV to 10 mV was applied, the equilibrium dissociation constant $(K_d)$ of $Cd^{2+}\;was\;39\;{\mu}M,\;K_d\;of\;Co^{2+}\;was\;100\;{\mu}M\;and\;K_d\;of\;Ni^{2+}];was];780{\mu}M.$ The principal findings of this study are as follows. First, the majority of $Ca^{2+}$ channels in rat chromaffin cells are well classified to L-type $Ca^{2+}$ channel in the view of kinetics and pharmacology. Second, all divalent cations tested could block the $Ca^{2+}$ current and the most potent blocker among the tested was $Cd^{2+}$.

• Journal of the Korean Society of Food Culture
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• v.19 no.6
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• pp.691-700
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• 2004

This study was conducted to examine the proximate composition, alginic acid and mineral contents and the types of calcium and magnesium in the parts(frond, stipe, sporophyll) of sea mustards. Carbohydrates and the crude fat was the highest in sporophyll. The contents of alginic acid were $25.9{\sim}32.2%$. Total alginic acid(32.2%) and insoluble alginic acid in water(27.7%) was e highest in sporophyll. Calcium and magnesium was the highest in frond. Phosphorous, potassium and sulfur was the highest in sporophyll. Iron, zinc and mangane was the highest in frond. Ca/P ratio in frond and stipe was about $1.7{\sim}1.8:1$ levels. Calcium and magnesium soluble in sodium chloride was the highest in sea mustards. Calcium and magnesium soluble in water was the highest in frond. Calcium and magnesium soluble in hydrochloric acid was the highest in sporophyll.