• Journal of Environmental Science International
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• v.30 no.3
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• pp.195-206
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• 2021

Contaminated marine sediment is a secondary pollution source in the coastal areas, which can result in increased nutrients concentrations in the overlying water. We analyzed the nutrients release characteristics into overlying water from sediments and the interaction among benthic circulation of nitrogen, phosphorus, iron, and sulfur were investigated in a preset sediment/water column. Profiles of pH, ORP, sulfur, iron, nitrogen, phosphorus pools were determined in the sediment and three different layers of overlying water. Variety types of sulfur in the sediments plays a significant role on nutrients transfer into overlying water. Dissimilatory nitrate reduction and various sulfur species interaction are predominantly embodied by the enhancing effects of sulfide on nitrogen reduction. Contaminant sediment take on high organic matter, which is decomposed by bacteria, as a result promote bacterial sulfate reduction and generate sulfide in the sediment. The sulfur and iron interactions had also influence on phosphorus cycling and released from sediment into overlying water may ensue over the dissolution of ferric iron intercede by iron-reducing bacteria. The nutrients release rate was calculated followed by release rate equation. The results showed that the sediments released large-scale quantity of ammonium nitrogen and phosphate, which are main inner source of overlying water pollution. A mechanical migration of key nutrients such as ammonia and inorganic phosphate was depicted numerically with Fick's diffusion law, which showed a fair agreement to most of the experimental data.

• Korean Journal of Microbiology
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• v.23 no.3
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• pp.177-183
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• 1985

Some properties of an extracellular cytosine deaminase produced from Arthrobacter sp.JH-13 were examined after 20-80% of ammonium sulfate fractionation. Among some substrates, this enzyme utilized cytosine and 5-fluorocytosine as a substrate. The optimum pH and temperature for the activity of this enzyme were found to be near 8.0 and $40^{\circ}C$, respectively. The ensyme was more stable in 0.2M of Tris-HCl buffer than 0.2M of potassium phosphate buffer. The enzyme was generally stable below $50^{\circ}C$, but inactivated completely at $70^{\circ}C$. 1mM of $Fe^{3+},\;K^+\;and\;Na^+$ increased the enzyme activity, but 0.01mM of $Co^{2+},\;Cu^{2+},\;Ni^{2+},\;Hg^{2+},\;Ag^{2+},\;Zn^{2+},\;Ba^{2+},\;and\;Mg^{2+}$ markedly inactivated the enzyme activity. 0.1mM of p-chloromercuribenzoate, trichloroacetic acid, and N-ethylmaleimide compleyely inhibited the enzyme activity, but 0.1mM of 2-mercaptoethanol slightly increased the enzyme activity.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.12
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• pp.1699-1705
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• 2011

Magnesium ammonium phosphate (MAP) was recovered from swine wastewater and the feasibility of reutilizing it as a slowly-releasing fertilizer was evaluated. Maize growth was investigated with normal and high application rates of MAP and a fused super phosphate (FSP) fertilizer. A total of 5 treatments ($T_0$ = control, $T_1$ = MAP based on 30 kg P $ha^{-1}$, $T_2$ = FSP based on 30 kg P $ha^{-1}$+urea equivalent to nitrogen of MAP applied in $T_1$, $T_3$ = MAP based on 40 kg P $ha^{-1}$, $T_4$ = FSP based on 40 kg P $ha^{-1}$+urea equivalent to nitrogen of MAP applied in $T_3$) were arranged with 3 replications. In the case of height and circumference, significant differences were found between controls and treated maize plants (p<0.01). However, no statistical differences were found between MAP- and FSP-urea treated maize. Leaf area and green biomass yield were significantly (p<0.01) higher in the treated group than control. Leaf area was also found significantly higher (p<0.01) in the higher MAP- treated group (2,374 $cm^2$ $plant^{-1}$) than other treatments. $N_2O$ emission was found to be lower in MAP treated soil than that from FSP-urea treated soil, which might be due to the slow releasing pattern of MAP. It could be assumed from the results that MAP would be an eco-friendly sustainable fertilizer source for crop production.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.192-197
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• 2005

The effects of macronutrients $(NO_3^-,\; NH_4^+\;and\;PO_4^{3-})$ on cell growth and triterpenoids production in Centella asiatica cell suspension cultures were analyzed using the Box­Behnken response surface model experimental design. In screening and optimization experiments, $PO_4^{3-}$ as a single factor significantly influenced cell growth where increasing the phosphate level from 0.1 to 2.4 or 2.6 mM, elevated cell growth from 3.9 to $14\~16g/L$. The optimum values predicted from the response surface model are 5.05mM $NH_4^+$, 15.0mM $NO_3^-$ and 2.6mM $PO_4^{3-}$, yielding 16.0g/L cell dry weight with $99\%$ fitness to the experimental data. While the $NH_4^+-NO_3^-$ interaction influenced cell growth positively in the optimization experiment, $NH_4^+$ and $NO_3^-$ as single factors; and interactions of $NO_3^--PO_4^{3-},\;NH_4^+-PO_4^{3-}$ and $NH_4^+-NO_3^-$ were all negative in the screening experiment. Cell growth and the final pH level were positively affected by $PO_4^{3-}$, but negatively affected by $NH_4^+\;and\;NH_4^+-PO_4^{3-}$ interactions. The different effects of factors and their interactions on cell growth and final pH are influenced by a broad or narrow range of macronutrient concentrations. The productions of triterpenoids however were lower than 4mg/g cell dry weight.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.109-113
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• 2017

Single analytical procedure including extraction, liquid chromatography, and mass spectrometric analysis was evaluated for the simultaneous measurement of lysophospholipids (LPLs). LPLs, particularly, lysophosphatidic acids (LPA) and sphingosine 1-phosphate (S1P) are lipid messengers ubiquitously found in various biological matrix. The molecular species mediate important physiological roles in association with many diseases (e.g. cancer, inflammation, and neurodegenerative disease), which emphasize the significance of the simple and reliable analytical method for biomarker discovery and molecular mechanistic understanding. Thus, we developed analytical method mainly focusing on, but not limited by those lipid species S1P and LPA using reverse phase liquid chromatography-tandem mass spectrometry (RPLC-ESI-MS-MS). Extraction method was modified based on Folch method with optimally minimal level of ionization additive (ammonium formate 10 mM and formic acid). Reverse-phase liquid-chromatography was applied for chromatographical separation in combination with negative ionization mode electrospray-coupled Orbitrap mass spectrometry. The method validation was performed on human blood plasma in a non-targeted lipid profiling manner with full-scan MS mode and data-dependent MS/MS. The proposed method presented good inter-assay precision for primary targets, S1P and LPA. Subsequent analysis of other types of LPLs identified a broad range of lysophosphatidylcholines (LPCs) and lysophosphatidyl-ethanolamines (LPEs).

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.81-89
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• 2001

In order to know relationships between green euglenoids and environmental factors, the species composition and density were assessed for 12 months together with environmental variables in the Jeonjucheon urban drainage, Korea. Nitrate was a high of 3.22 mg/1 in June and phosphate concentration was over 0.71 mg/l in the winter. The euglenoids totaled 5 genera and 71 species throughout the year, increasing in the early summer (35 to 42 texa) and decreasing in the winter (below 20 taxa). The number of green euglenoids positively correlated with surface water temperature. the total density of the green euglenoids showed a typical bimodal pattern, being maximal in the winter (5,394 cells/ml in June). The winter peak was a result of active growths of Euglena caudata, E. geniculata and E. viridis, however, each of which positively correlated with the phosphate. The early summer peak was attributed to Euglena deses, Lepocinclis ovum, and Phacus trypanon, each of which positively correlated with the ammonium and nitrate. The complete bimodal spectrum of species number and density of green euglenoids provides a sensitive image in detecting the changes of environmental variables in polluted waters such as Jeonjucheon.

• Journal of the Korean Society of Food Culture
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• v.5 no.2
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• pp.269-274
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• 1990

This study was conducted to determine invertase activity in persimmon during the drying process and characterize the purified enzyme. As drying proceeded, invertase activity increased until 10 days and decreased gradually afterwards. Invertase in persimmon fruit was extracted with 250 mM potassium phosphate sulfate buffer at pH 7.4. The enzyme was purified by means of ammonium sulfate fractionation, column chromatography on DEAE-cellulose and gel filtration on Sephadex G-200 column. The optimal temperature of enzyme was $40^{\circ}C$ and optimal pH was 5.0 and 6.0 for sucrose and raffinose, respectively. The enzyme was stable up to $50^{\circ}C$ and pH 3-6. The Km value of the enzyme, with sucrose as a substrate, was 2.5mM. Electrophoretic pattern of purified enzyme solution showed a single band.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.285-292
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• 2008

This study was initiated to evaluate the Phosphorus(P) leaching potential in the putting green soils and P uptake by the turfgrass in the golf course using the P fertilizers. The turfgrass, Floradwarf bermudagrass(Cynodon dactylon L. PERS,) was planted and grown in the mixture of sand and peat moss in this lysimeter study. Five representative P fertilizers, such as, ammonium polyphosphate (APP), monopotassium phosphate (MKP), MAP(monoammonium phosphate), 0-20-20(liquid), and concentrated superphosphate(CSP, solid) were used in this study. Based on the total P quantity of leachate collected during the whole 12 weeks, MKP and APP are the first group of P fertilizers contributing to the leaching of P, then MAP and 0-20-20 are the second group of P fertilizers causing the P leaching. Finally, CSP is the third group of P fertilizer resulting in the P leaching. However, most of P applied and collected in the lysimeter were leached during the first period of two and four weeks, compared to that of P leached during the second period of six, eight, ten, and twelve weeks. Applications of MAP, APP and CSP, MKP and 0-20-20 in order produced the largest amount of total dry matter. However, APP, MKP and MAP, CSP and 0-20-20 in order showed the largest amount of P uptake. Therefore, based on the data of P leaching, dry matter production, and plant P uptake, it appears that CSP, 0-20-20, and MAP are the environmentally sound fertilizers recommended in the turfgrass putting green soil of golf course.

• Journal of Climate Change Research
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• v.6 no.3
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• pp.249-256
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• 2015

This study was conducted to investigate the effects of different levels and types of nitrogen fertilizer on seedlings and soil chemical properties in a semi-arid area, Mongolia. 2-year-old Populus sibirica and 4-year-old Ulmus pumila seedlings were planted in May 2014. Six treatments with three levels of nitrogen (low-level: urea $5g\;tree^{-1}$; medium-level: urea $15g\;tree^{-1}$, ammonium sulfate $33g\;tree^{-1}$, urea $15g\;tree^{-1}$ with potassium phosphate $10g\;tree^{-1}$; high-level: urea $30g\;tree^{-1}$) were applied and for the medium-level of nitrogen, different types of fertilizer were treated. Survival rate, root collar diameter (RCD) growth rate, leaf nitrogen concentration of seedlings, and soil chemical properties were determined in August 2014. The seedling survival rate of both species decreased as the level of nitrogen increased. This result can be explained by water stress caused by nitrogen fertilization in arid regions. The RCD growth rate of P. sibirica was significantly decreased by the treatment of high-level of nitrogen due to excessive nitrogen fertilization, and was increased by the treatment of ammonium sulfate due to sulfur which might promote nitrogen uptake. The leaf nitrogen concentration of P. sibirica did not change by the treatment of low-level of nitrogen, and was increased by the treatment of medium-level of nitrogen. There were no significant differences in the RCD growth rate and the leaf nitrogen concentration of U. pumila among the six treatments. None of soil chemical properties was affected by nitrogen fertilization. Overall, the low-level of nitrogen showed no effect on seedlings and soil chemical properties, except on survival rate of U. pumila and the high-level of nitrogen was considered excessive fertilization. Continuous monitoring of medium-level nitrogen fertilization including the ammonium sulfate, which increased early growth of seedlings, would be needed to elucidate the effect of fertilization on seedling growth and soil properties in a semi-arid region.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.2
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• pp.110-116
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• 1982

A water culture was conducted with 5 levels of nitrate-ammonium ratio (NAR: 10:0, 7:3, 5:5, 3:7, 0:10) to study the ionic balance, cation-anion (C-A) in mulberry leaves and to determine the optimum NAR for the greatest leaf yields. The results were as follows: 1. The growth rate of mulberry plants was the greatest at 7:3 NAR. 2. Magesium in the mulberry leaves was not affected by NAR. By lowering NAR, calcium content decreased more than potassium content increased, consequently lowering the sum of cation content (${\sum}C$). However, the sum of anion (${\sum}A$) increased because of increments of sulphate, chloride and especially phosphate. 3. Ionic balance in the mulberry leaves deceased from 727 to 116 me/Kg dry matter with increasing ammonium levels of 0 to 100% in the nutrient solution.