• Fisheries and Aquatic Sciences
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• v.24 no.7
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• pp.260-275
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• 2021

Aquaponics is a cultivation system that combines aquaculture and agricultural hydroponics. This study investigated the productivity of leafy vegetables cultivated in the hybrid biofloc technology-aquaponics (HBFT-AP) using Japanese eel fed two kinds of diets (Mash, commercial powdered feed and extruded pellet [EP]) and hydroponics (HP).The mash was fed to the fish in a type of a dough mixed with water for 6 weeks (Exp1) and switched to the EP containing 2.7% monobasic potassium phosphate (MKP) for subsequent 6 weeks (Exp2). Leafy vegetables of 8 cultivar were employed in the experiment and water quality [dissolved oxygen (DO, mg/L), pH, water temperature (℃), electrical conductivity (EC; ㎲/cm), turbidity (NTU), TAN (NH₃ + NH₄⁺) (mg /L), NO₂-N (mg/L), NO₃-N (mg/L) and PO₄-P (mg/L)] was measured 6 times a week. Leafy vegetable productivity (HBFT-AP vs HP) was compared in respective experiment, which was similar or somewhat higher in HBFT-AP. During the 12-week feeding trial, concentrations of nitrite (NO₂-N) and phosphorus (PO₄-P) were kept low in variability while total ammonia nitrogen (TAN) and NO₃-N levels increased with time in HBFT-AP. At the end of two feeding trials, values of weight gain (WG, %), feed efficiency (FE, %), specific growth rate (SGR, %) and protein efficiency ratio (PER) were higher in Exp2 than in Exp1. As well, higher values in hematocrit (PCV, %), plasma K (mEq/L) and inorganic phosphorus (mg/dL) were found (p < 0.05) in Exp2 where fish were fed the EP (EP: 38.60%, 2.80 mEq/L and 7.04 g/dL; Mash: 33.20%, 1.95 mEq/L and 5.50 g/dL). Leafy vegetables in HBFT-AP using Japanese eel fed the EP with MKP 2.7% had a productivity similar (4 kinds of cultivar) or somewhat higher (4 kinds of cultivar) compared to those in HP. Also, Japanese eel fed the EP showed higher values of Pi (m/dL) and K (mEq/L) in plasma compared to those fed commercial powder diet.

• Journal of Life Science
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• v.25 no.11
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• pp.1311-1318
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• 2015

The effects of fruit maturation on changes in the total phenolics, flavonoids, and carotenoids of methanolic extracts of Citrus sudachi, in addition to its antioxidant and antidiabetic activities, were determined. Generally, the concentration of these chemical constituents increased as C. sudachi reached maturity. C. sudachi contained high levels of total phenolics, flavonoids, and carotenoids at maturity, contributing 6339.5 mg of gallic acid equivalent per 100 g, 2364.2 mg of rutin equivalent per 100 g, and 678.7 mg/ml, respectively. The scavenging activities of 1,1-diphenyl-2-picryl hydrazyl (DPPH), hydrogen peroxide and nitric oxide radicals and the reducing power of mature fruits were significantly higher at all data points than those of immature fruits (p<0.05). In contrast, the ferrous ion chelating activity of mature and immature C. sudachi fruits was similar. The 50% effective concentrations (EC₅₀) of mature fruits were 4.1±0.10 mg/ml for scavenging DPPH radicals, 3.1±0.02 mg/ml for scavenging hydrogen peroxide, 3.9±0.01 mg/ml for scavenging nitric oxide, and 3.8±0.02 mg/ml for chelating ferrous ion. The antidiabetic activity of C. sudachi was studied in vitro using the α-glucosidase inhibitory method. The inhibitory activity of mature C. sudachi fruits on α-glucosidase was higher than that of immature fruits. These results suggest that the content of bioactive compounds and the antioxidant and antidiabetic activities of C. sudachi change during maturation. These findings can be further extended to exploit them for their possible application for the preservation of food products, as well as their use as health supplements and nutraceuticals.

• Journal of Applied Biological Chemistry
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• v.44 no.4
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• pp.199-201
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• 2001

A phenolic substance was isolated from the bark of Pinus koraiensis. It was identified to be pinostilbenoside. Its anti-$LTD_4$ activity was evaluated using isolated guinea pig trachea, and its half maximal bronchodilating activity ($EC_{50}$) was $593{\pm}56{\mu}g{\cdot}ml^{-1}$. Because it is not known that stilbene derivatives possess anti-asthmatic activity through $LTD_4$ antagonism, here we report the result.

• Fisheries and Aquatic Sciences
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• v.22 no.10
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• pp.22.1-22.7
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• 2019

The functional peptides from protein hydrolysates of various fishery sources have been identified such as antioxidant activity. The main intention of this study was purification and characterization of antioxidative peptide from black eelpout muscle. The antioxidative peptides were purified from black eelpout (Lycodes diapterus) muscle using different proteases. Antioxidant activity of black eelpout hydrolysates was evaluated using DPPH radical scavenging activity. Among six hydrolysates, the pepsin hydrolysate had the highest antioxidant activity compared to the other hydrolysates. Therefore, it was further purified and a peptide with seven amino acid residues of DLVKVEA (784 Da) was identified by amino acid sequence analysis. The EC₅₀ value for scavenging DPPH radicals by purified peptide was 688.77 μM. Additionally, the purified peptide exhibited protective effect against DNA damage induces by oxidation in mouse macrophages (RAW 264.7 cells). The results of this study suggest that black eelpout muscle protein hydrolysate could potentially contribute to development of bioactive peptides in basic research.

• Journal of Soil and Groundwater Environment
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• v.21 no.2
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• pp.15-21
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• 2016

The objective of this study was to determine the feasibility of recycled phosphogypsum (PG) as an embankment material with soil by performing batch and column ecotoxicity experiments. A. salina, D. magna, O. latipes and S. capricornutum were selected for the experiment. The effective concentration (EC₅₀) of D. magna was the lowest value, 1.29 mg/L. The survival rates of A. salina, D. magna and O. latipes were more than 90% in the presence of PG leachate in the column test. The toxicity unit (TU) for the organisms was less than 1, indicating that no significant ecotoxicity effect was found. These findings suggested that PG could be recycled for use as an embankment and landfill material with soil.

• Elastomers and Composites
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• v.50 no.4
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• pp.297-303
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• 2015

Ammonium polyphosphate-polyurethane foam composite (APP-PUF) was prepared from poly(adipate)diol/ammonium polyphosphate composite (f = 2), polyether polyol (f = 4.6), and PMDI (f = 2.5). As a blowing agent, $H_2O$ was used at various concentrations. The thermal decomposition behavior, morphology, closed-cell content, and density of APP-PUF were characterized. At the $H_2O$ concentrations lower than 3.5 php, the cell size of pure polyurethane foams (PUF) and APP-PUFs were close each other. As the $H_2O$ concentration became greater than 5.0 php, the cell size of the PUFs greatly increased compared to that of APP-PUFs. Addition of 1.5~1.9 wt% ammonium polyphosphate to the PUFs greatly enhanced the thermal stability of the PUFs, so 50 wt% residual temperature of APP-PUFs increased to $380{\sim}488^{\circ}C$, which were $30{\sim}70^{\circ}C$ higher than those of the PUFs. Thermal stability of the PUFs and APP-PUFs increased with $H_2O$ content and then decreased once $H_2O$ content exceeded 5 php.

• Biomolecules & Therapeutics
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• v.28 no.2
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• pp.145-151
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• 2020

Alzheimer's disease (AD) is a devastating neurodegenerative disease and a major cause of dementia in elderly individuals worldwide. Increased deposition of insoluble amyloid β (Aβ) fibrils in the brain is thought be a key neuropathological hallmark of AD. Many recent studies show that natural products such as polyphenolic flavonoids inhibit the formation of insoluble Aβ fibrils and/or destabilize β-sheet-rich Aβ fibrils to form non-cytotoxic aggregates. In the present study, we explored the structure-activity relationship of naturally-occurring biflavonoids on Aβ amyloidogenesis utilizing an in vitro thioflavin T assay with Aβ1-42 peptide which is prone to aggregate more rapidly to fibrils than Aβ1-40 peptide. Among the biflavonoids we tested, we found amentoflavone revealed the most potent effects on inhibiting Aβ1-42 fibrillization (IC₅₀: 0.26 µM), as well as on disassembling preformed Aβ1-42 fibrils (EC₅₀: 0.59 µM). Our structure-activity relationship study suggests that the hydroxyl groups of biflavonoid compounds play an essential role in their molecular interaction with the dynamic process of Aβ1-42 fibrillization. Our atomic force microscopic imaging analysis demonstrates that amentoflavone directly disrupts the fibrillar structure of preformed Aβ1-42 fibrils, resulting in conversion of those fibrils to amorphous Aβ1-42 aggregates. These results indicate that amentoflavone affords the most potent anti-amyloidogenic effects on both inhibition of Aβ1-42 fibrillization and disaggregation of preformed mature Aβ1-42 fibrils.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.347-355
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• 2016

An exo-β-D-glucosaminidase (AorCsxA) from Aspergillus oryzae FL402 was heterologously expressed and purified. The deduced amino acid sequence indicated that AorCsxA belonged to glycoside hydrolase family 2. AorCsxA digested colloid chitosan into glucosamine but not into chitosan oligosaccharides, demonstrating exo-β-D-glucosaminidase (CsxA) activity. AorCsxA exhibited optimal activity at pH 5.5 and 50℃; however, the enzyme expressed in Pichia pastoris (PpAorCsxA) showed much stronger thermostability at 50℃ than that expressed in Escherichia coli (EcAorCsxA), which may be related to glycosylation. AorCsxA activity was inhibited by EDTA and most of the tested metal ions. A single amino acid mutation (F769W) in AorCsxA significantly enhanced the specific activity and hydrolysis velocity as revealed by comparison of V_max and k_cat values with those of the wild-type enzyme. The three-dimensional structure suggested the tightened pocket at the active site of F769W enabled efficient substrate binding. The AorCsxA gene was heterologously expressed in P. pastoris, and one transformant was found to produce 222 U/ml activity during the high-cell-density fermentation. This AorCsxA-overexpressing P. pastoris strain is feasible for large-scale production of AorCsxA.

• Journal of the Korean Society of Food Culture
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• v.36 no.6
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• pp.622-632
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• 2021

This study was conducted to find out the optimal solvent extraction method [Distilled water (DW), 70% ethanol, 99% ethanol] of mushrooms, including Pleurotus ostreatus (Jacq.) Que, Pleurotus eryngii and Flammulina velutipes and improve their usability as natural antioxidants. To analyze antioxidant activities in each mushroom, total polyphenol, flavonoid contents, 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical (ABTS⁺) and fluorescence recovery after photobleaching (FRAP) were measured. All mushrooms showed the highest total polyphenol contents in DW mushroom extract (p<0.001). Total flavonoid contents were the highest in P. eryngii and F. velutipes DW and 70% ethanol mushroom extracts (p<0.05). All mushrooms showed the highest activities using DPPH and FRAP assays in the DW extraction method (p<0.001). P. ostreatus (Jacq.) Que and P. eryngii showed the highest ABTS⁺ radical scavenging activity in the DW extraction method, and F. velutipes showed the highest activity in the 70% ethanol extraction method (p<0.001). As a result of comparing IC₅₀ values of DPPH and ABTS+ radicals and FRAP EC₅₀ values, the DW P. ostreatus (Jacq.) Que extract showed high antioxidant activities (p<0.001). Pearson's correlation between total polyphenol contents and antioxidant activities showed a positive correlation in all mushrooms (p<0.01). Therefore, extraction of the mushrooms with DW can enhance the extraction of effective bioactive substances and antioxidant activity.

• Journal of Environmental Science International
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• v.30 no.11
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• pp.945-956
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• 2021

In this study, the effects of single and binary heavy metals toxicity on the growth and phosphorus removal ability of Bacillus sp.. known as be a phosphorus-removing microorganism, were quantitatively evaluated. Cd, Cu, Zn, Pb, Ni were used as heavy metals. As a result of analysis of variance of the half of inhibition concentration and half of effective concentration for each single heavy metal treatment group, the inhibitory effect on the growth of Bacillus sp. was Ni < Pb < Zn < Cu < Cd. And the inhibitory effect on phosphorus removal by Bacillus sp. was Ni < Pb < Zn < Cu < Cd. When analyzing the correlation between growth inhibition and phosphorus removal efficiency of a single heavy metal treatment group, a negative correlation was found (R² = 0.815), and a positive correlation was found when the correlation between IC₅₀ and EC₅₀ was analyzed (R² = 0.959). In all binary heavy metal treatment groups, the interaction was an antagonistic effect when evaluated using the additive toxicity index method. This paper is considered to be basic data on the toxic effects of heavy metals when phosphorus is removed using phosphorus removal microorganisms in wastewater.