• Korean Journal of Microbiology
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• v.53 no.4
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• pp.251-256
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• 2017

Some rhizobacteria were isolated, that have copper resistance and can confer copper resistance to plants allowing growth under copper stress. Isolated strains Pseudomonas veronii MS1 and P. migulae MS2 produced 0.13 and 0.26 mmol/ml of siderophore, that is a metal-chelating agent, and also showed 64.6 and 77.9% of biosorption ability for Cu in 20 mg/L Cu solution, respectively. Copper can catalyze a formation of harmful free radicals, which may cause oxidative stress in organisms. Removal activity of 1,1-diphenyl-2-picryl hydrazyl radical and antioxidant capacity of strains MS1 and MS2 increased up to 82.6 and 78.1%, respectively compared to those of control at 24 h of incubation. They exhibited 7.10 and $6.42{\mu}mol$ ${\alpha}$-ketobutyrate mg/h of 1-aminocyclopropane-1-carboxylic acid deaminase activity, respectively, which reduced levels of stress hormone, ethylene in plants, and also produced indole-3-acetic acid and salicyclic acid that can help plant growth under abiotic stress. All these results indicated that these copper-resistant rhizobacteria could confer copper resistance and growth promotion to plants.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.861-867
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• 2019

$Li_4Ti_5O_{12}$ is a promising next-generation anode material for lithium-ion batteries due to excellent cycle life, low irreversible capacity, and little volume expansion during charge-discharge process. However, it has poor charge capacity at high current density due to its low electrical conductivity. To improve this weakness, porous $Li_4Ti_5O_{12}$ was synthesized by sol-gel method with P123 as chelating agent. The physical characteristics of as-prepared sample was investigated by XRD, SEM, and BET analysis, and electrochemical properties were characterized by cycle performance test, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS). $Li_4Ti_5O_{12}$ synthesized by 0.01mol ratio of P123/Ti showed most unified particle size, high specific surface area, and relatively high porosity. EIS analysis showed that depressed semicircle size was remarkably reduced, which suggested resistance value in electrode was decreased. Capacity in rate performance showed 178 mAh/g at 0.2C, 170 mAh/g at 0.5C, 110 mA/h at 5C, and 90 mAh/g at 10C. Capacity retention also showed 99% after rate performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.527-534
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• 2019

Japanese sumac (Rhus javanica) is one of the common herbaceous plants growing over the country. This study was conducted to investigate the extraction characteristics and physiological activities inluding nitrite scavenging ability of the water extracts from leaf, fruit and bark of Japanease sumac. Extraction yield was 6.62~13.84%, free amino acids were detected as 24 kinds with 37.9 mg/100g in leaf extract, 23 kinds with 27.0 mg/100g in fruit extract and 27 kinds with 39.0 mg/100g in bark extract, respectively, and seven kinds essential amino acids were detected. Total contents of flavonoids equivalent to naringin were 587.2 mg/100g in bark extract, 557.3 mg/100g in fruit extract and 379.9 mg/100g in leaf extract, respectively. Total contents of phenolics equivalent to gallic acid were 111.2 mg/100g in leaf extract, 108.4 mg/100g in fruit extract and 80.4 mg/100g in bark extract, respectively. The nitrite scavenging ability of extracts was order of 61.93% in bark extract>57.38% in fruit extract>55.49% in leaf extract, and was 78.1~100% of those of BHT (butylated hydroxytoluene) equivalents at pH 1.2. The electron donating ability was order of 47.38% in fruit extract>43.06% in leaf extract>38.55% in bark extract, and was compared to 65.6%, 58.8% and 53.6% of those of BHT equivalents, respectively. The reduction power was evaluated to 37% higher in leaf extract, 43% higher in fruit extract and 46% higher in bark extract than those of BHT equivalents. The metal chelating ability of extracts was considerably low and was order of 27.3% in bark extract>20.6% in leaf extract>11.2% in fruit extract.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.555-566
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• 2018

Two rhizobacteria Bacillus aryabhattai H26-2 and B. siamensis H30-3 were evaluated whether they are involved in stress tolerance against drought and high temperature as well as fungal infections in Chinese cabbage plants. Chinese cabbage seedlings cv. Ryeokgwang (spring cultivar) has shown better growth compared to cv. Buram-3-ho (autumn cultivar) under high temperature conditions in a greenhouse, whilst there was no difference in drought stress tolerance of the two cultivars. In vitro growth of B. aryabhattai H26-2 and B. siamensis H30-3 were differentially regulated under PEG 6000-induced drought stress at different growing temperatures (30, 40 and $50^{\circ}C$). Pretreatment with B. aryabhattai H26-2 and B. siamensis H30-3 enhanced the tolerance of Chinese cabbage seedlings to high temperature, but not to drought stress. It turns out that only B. siamensis H30-3 showed in vitro antifungal activities and in planta crop protection against two fungal pathogens Alternaria brassicicola and Colletotrichum higginsianum causing black spots and anthracnose on Chinese cabbage plants cv. Ryeokgwang, respectively. B. siamensis H30-3 brings several genes involved in production of cyclic lipopeptides in its genome and secreted hydrolytic enzymes like chitinase, protease and cellulase. B. siamensis H30-3 was found to produce siderophore, a high affinity iron-chelating compound. Expressions of BrChi1 and BrGST1 genes were up-regulated in Chinese cabbage leaves by B. siamensis H30-3. These findings suggest that integration of B. aryabhattai H26-2 and B. siamensis H30-3 in Chinese cabbage production system may increase productivity through improved plant growth under high temperature and crop protection against fungal pathogens.

• Journal of Mushroom
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• v.17 no.3
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• pp.152-161
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• 2019

Phallus impudicus var. impudicus L. is an edible mushroom that has long been used as folk medicine in China. The aim of this study was to evaluate the antioxidant, anti-cholinesterase, and inflammation inhibitory activities of a methanol extract of fruiting bodies of P. impudicus var. impudicus L. The extract exhibited good 1,1-diphenyl-2-picrylhydrazyl scavenging activity, excellent ferrous ion chelating activity, and moderate hydroxyl radical scavenging activity compared with BHT at 2.0 mg/ml. However, the reducing power of the extract was significantly lower than that the BHT positive control. Although the inhibitory activities of methanol extract on acetylcholinesterase and butyryl cholinesterase were significantly lower than the galanthamine positive control at the concentration tested, the inhibition of acetylcholinesterase and butyryl cholinesterase was 52.83% and 55.17%, respectively, at 1.0 mg/ml. The methanol extract also demonstrated excellent inhibition of inflammation-related activities, such as production of nitric oxide in lipopolysaccharide-induced RAW 264.7 macrophage cells and acute edema induced by administration of carrageenan on the hind paw of rats. The collective results suggest that the fruiting body of P. impudicus var. impudicus L. might be a good source of antioxidant, anti-cholinesterase, and anti-inflammation compounds.

• Journal of Life Science
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• v.29 no.2
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• pp.231-238
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• 2019

This study evaluated the antioxidant activity of the extract and fractions of Alnus firma. Alnus firma had the highest total phenolic content ($452.80{\pm}7.01{\mu}g$ gallic acid equivalents/mg) in a methanol (MeOH) fraction and the highest total flavonoid content ($112.29{\pm}11.14{\mu}g$ rutin equivalents/mg) and antioxidant capacity ($936.23{\pm}0.07{\mu}g$ ${\alpha}$-tocopherol equivalents/mg) in an ethylacetate (EA) fraction. The antioxidant activities of various solvent extract fractions of Alnus firma were evaluated using various antioxidant assays, including ${\beta}$-carotene-linoleate assay, reducing power assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, metal chelating activity assay, superoxide anion radical scavenging assay, and lipid peroxidation inhibition assay using the ferric thiocyanate method. These activities were compared with those of ascorbic acid, butylated hydroxyanisole (BHA), gallic acid (GA), butylated hydroxytoluene (BHT), and ${\alpha}$-tocopherol. First, at a $250{\mu}g/ml$ concentration, the EA and MeOH fractions of A. firma showed 92.43% and 89.20% DPPH radical scavenging activity, respectively. Second, $50{\mu}g/ml$ of the EA fraction exhibited 72.49% superoxide anion radical scavenging activity, a little greater than the same dose of GA (60.88%). Finally, 0.5 and 1 mg/ml of the EA fraction showed 73.45% and 73.29% inhibition of peroxidation in the ${\beta}$-carotene-linoleic acid system, respectively. The decreasing order of reducing power was EA fraction > n-butanol (BuOH) fraction > dichloromethane (DCM) fraction > n-hexane (HX) fraction. The results obtained in the present study indicated that Alnus firma can be used as an easily accessible potential source of natural antioxidants.

• Journal of Life Science
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• v.31 no.5
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• pp.520-526
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• 2021

Microbial protein is one of the sources of protein in the rumen and can also be the source of glutamate production. Glutamic acid is used as fuel in the metabolic reaction in the body and the synthesis of all proteins for muscle and other cell components, and it is essential for proper immune function. Moreover, it is used as a surfactant, buffer, chelating agent, flavor enhancer, and culture medium, as well as in agriculture for such things as growth supplements. Glutamic acid is a substrate in the bioproduction of gamma-aminobutyric acid (GABA). This review provides insights into the role of glutamic acid and glutamic acid-producing microorganisms that contain the glutamate decarboxylase gene. These glutamic acid-producing microorganisms could be used in producing GABA, which has been known to regulate body temperature, increase DM intake and milk production, and improve milk composition. Most of these glutamic acid and GABA-producing microorganisms are lactic acid-producing bacteria (LAB), such as the Lactococcus, Lactobacillus, Enterococcus, and Streptococcus species. Through GABA synthesis, succinate can be produced. With the help of succinate dehydrogenase, propionate, and other metabolites can be produced from succinate. Furthermore, clostridia, such as Clostridium tetanomorphum and anaerobic micrococci, ferment glutamate and form acetate and butyrate during fermentation. Propionate and other metabolites can provide energy through conversion to blood glucose in the liver that is needed for the mammary system to produce lactose and live weight gain. Hence, health status and growth rates in ruminants can be improved through the use of these glutamic acid and/or GABA-producing microorganisms.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.252-259
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• 2021

Barley contains health-beneficial compounds, such as phenolic acids, flavonoids, lignans, and tocopherols. The antioxidant activities of pearled and wholegrain hull-less, premature, and black barley harvested in Jeju were investigated by measuring total phenolic content (TPC), total flavonoid content (TFC), phenolic compounds, tocopherols (T), and tocotrienols (T3), along with their in vitro antioxidant activities. Consequently, TPC and TFC in wholegrain barley groups were higher than those in pearled barley. Gallic acid (1.55-2.98 ㎍/g) and protocatechuic acid (0.67-2.84 ㎍/g) were the predominant phenolic compounds in barley. Total T and T3 concentrations of wholegrain barley groups were significantly higher than those of pearled barley (p<0.05). Except for the metal chelating effect and reducing power, the in vitro antioxidant activities of wholegrain barley were significantly higher than those of pearled barley. These results indicate that wholegrain Jeju barley can be used as a natural antioxidant source in the food industry.

• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.431-436
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• 2023

As the industry develops, the amount of heavy metals flowing into the ecosystem is increasing. Heavy metals are difficult to decompose and remain in the ecosystem for a long time and cause toxicity, which is removed by physicochemical methods such as adsorption, filtration, and chemical precipitation during water treatment. In this study, Alginate bead was selected as a chelating resin for adsorbing and removing heavy metals, and the Jellyfish Extract at Immunity reaction (JEI) were mixed to evaluate the adsorption efficiency of heavy metals accordingly. beads mixed with JEI showed high adsorption efficiency in lead (79-99%) and copper (64-70%) according to the characteristics of Alginate, and low adsorption efficiency in cadmium (25-37%) and zinc (5-6%). Although heavy metal adsorption did not increase in proportion to the content of JEI, 50% and 100% JEI beads showed significant increases. As a result of applying the reaction rate equation, it was found that it was more suitable for the pseudo-secondary reaction equation than the pseudo-first reaction equation.

• Restorative Dentistry and Endodontics
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• v.27 no.6
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• pp.577-586
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• 2002

The purpose of this in vitro study was to compare the effects of root canal cleanness following two Ni-Ti rotary instruments with different rake angle. Thirty-six sound, extracted human premolars with single root were randomly divided into three groups. The used rotary instruments were HEROShaper (Group 1, Micro-Mega, Besancon, France, n=12) and ProFile (Group 2, Maillefer, Ballaigues, Switzerland, n=12). Control group (n=12) was only extirpated with barbed broach (Mani, Matsutani Seisakusho Co., Japan) Group 1 & 2 teeth were prepared to a #40/.04 taper at the apex followed by 1 mm using crown-down technique. After canal preparation and frequent irrigation with 5.25% sodium hypochlorite, the roots split longitudinally into a bucco-lingual direction. Root halves were cross-sectioned in apical third portion again. All root specimens were processed for SEM investigation and photographed. Separate evaluations by one endodontist were undertaken for smear layer on prepared walls with a five score-index for each using reference photograph in root halves. The penetration depth of smear layer into dentinal tubules was also estimated in the other halves. Following results were obtained: 1. Smear layer was observed on all the prepared walls with two experimental groups except control group. 2. Smear layer characteristics in two experimental groups; 1) HEROShaper group showed snowy, dusty appearance and were shown open dentinal tubuli on the prepared walls of almost specimens, and the thickness of smear layer covering onto dentinal surfaces was within 1-2 ${\mu}m$ in a few specimens. 2) ProFile group showed shiny, burnished appearance and complete root canal wall covered by a homogenous smear layer with no open dentinal tubuli in all specimens. The penetration of smear layer into dentinal tubules was found in all specimens and the thickness was at 2-4 ${\mu}m$ in all specimens. These results demonstrated that a completely clean root canal could not be achieved regardless of positive or negative rake angle, which is in accordance with the majority of previous studies on root canal cleanliness In conclusion, through irrigation with antibacterial solutions or chelating agents is recommended to remove the smear layer on prepared canal wall in spite of Ni-Ti instrumentation.