• Korean Journal of Environmental Agriculture
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• v.20 no.5
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• pp.340-345
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• 2001

High rates of nitrogen fertilization dangerously increase the nitrate content of vegetable crops, and the accumulation of nitrate in edible crops is undesirable because of potential risks to human health. Micronutrient solution containing Cu, Mn, Mo, Zn was tested for the suppression of nitrate accumulation in lettuce grown in pots treated with Mg fertilizer under a greenhouse condition. The micronutrient solution was sprayed on leaves at 3 and 4 weeks after transplanting of 20-day old seedlings. Plants were harvested after 5-week growth, and yield, contents of chlorophyll, sugar, micronutrient and nitrate, and also nitrate reductase activity were measured. Fresh weight of lettuce was significantly increased by the application of Mg and micronutrients, and the effect was the most significant in the Mg+micronutrient treatment. Also contents of chlorophyll and micronutrients were higher in the plants of micronutrient treatments. Contents of nitrate were reduced by about 14-18% in lettuce with Mg and/or micronutrient applications. Compared to the plants of control treatment, nitrate reductase activity was also higher in those plants treated with micronutrients, and in the treatment of Mg+micronutrients the enzyme activity was six times as high as that of control treatment. Although the effect of mineral nutrients on the suppression of nitrate accumulation in lettuce was relatively small in this study, an appropriate supply of mineral nutrients could be one of the solutions for the nitrate accumulation in vegetables.

• Applied Biological Chemistry
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• v.45 no.3
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• pp.129-133
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• 2002

Suppression of nitrate accumulation in spinach and lettuce through foliar application of chitosan formula containing micronutrients is related with the increase of the nitrate reductase (NR) activity. If NR in spinach were highly expressed to increase the assimilatory activity, nitrate content could be reduced. For this, NR cDNA was cloned from the isolated mRNAs of spinach using reverse transcriptase-PCR. Nucleotide sequence of cloned spinach NR cDNA showed highly deduced amino acid sequence identity ($71{\sim}82%$) with other known plant NR genes. Only two nucleotide-base differences were observed in the cloned NR cDNA compared with that of the published spinach NR cDNA.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.10
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• pp.1433-1441
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• 2015

This study examined changes of rumen fermentation, ruminal bacteria biodiversity and abundance caused by nitrate addition with Ion Torrent sequencing and real-time polymerase chain reaction. Three rumen-fistulated steers were fed diets supplemented with 0%, 1%, and 2% nitrate (dry matter %) in succession. Nitrate supplementation linearly increased total volatile fatty acids and acetate concentration obviously (p = 0.02; p = 0.02; p<0.01), butyrate and isovalerate concentration numerically (p = 0.07). The alpha (p>0.05) and beta biodiversityof ruminal bacteria were not affected by nitrate. Nitrate increased typical efficient cellulolytic bacteria species (Ruminococcus flavefaciens, Ruminococcus ablus, and Fibrobacter succinogenes) (p<0.01; p = 0.06; p = 0.02). Ruminobactr, Sphaerochaeta, CF231, and BF311 genus were increased by 1% nitrate. Campylobacter fetus, Selenomonas ruminantium, and Mannheimia succiniciproducens were core nitrate reducing bacteria in steers and their abundance increased linearly along with nitrate addition level (p<0.01; p = 0.02; p = 0.04). Potential nitrate reducers in the rumen, Campylobacter genus and Cyanobacteria phyla were significantly increased by nitrate (p<0.01; p = 0.01).To the best of our knowledge, this was the first detailed view of changes in ruminal microbiota by nitrate. This finding would provide useful information on nitrate utilization and nitrate reducer exploration in the rumen.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.119-128
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• 2004

The nitrate concentrations in PM$_{2.5}$ and TSP measured at Gosan, Jeju Island, Korea, between March 1998 and February 2002, are discussed. Especially, the characteristics of high nitrate concentration days were analyzed. High nitrate concentration cases in PM$_{2.5}$ were highly correlated with anthropogenic species such as NH$_4$$^{[-10]}$ , and high nitrate concentration cases in TSP were highly correlated with crustal species such as nss-Ca$^{2+}$ and nss -Mg$^{2+}$ Backward trajectory analysis results show the cases of high correlation between nitrate and anthropogenic species occurred when the air parcels moved from China, and the cases of high correlation between nitrate and crustal species occurred when the air parcels moved from Mongolia. Also, high nitrate concentration cases occurred most often in spring (65%) when the air parcels moved from Mongolia and China.ina.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.334-337
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• 2002

The drinking water industry faces a growing number of difficultiesin the treatment of groundwater for drinking water production. Groundwater sources are frequently contaminated with nitrates and phosphates due to usage of chemical fertilizer In this study, feasibility of micellar enhanced ultrafiltation (MEUF) was investigated to remediate groundwater contaminated with nitrate and phosphate. Ultrafiltration membrane was cellulose acetate with molecular weight cut off (MWCO) 10,000 and celtyl pyridinium chloride (CPC) was used to form pollutant-micelle complex with nitrate and phosphate. The results show that nitrate and phosphate rejections are satisfactory. The removal efficiency of nitrate and phosphate show 80% and 84% in single pollutant system, respectively with 3 molar ratio of CPC to pollutants. In the multi-pollutant systems, the removalefficiency increased to 90 % and 89 % for nitrate and phosphate, respectively, The presence of nitrate in the solutions did not affect the removal of phosphate and that of phosphate did not affect the removal of nitrate. The concentration of CPC in the permeate and removal efficiency of CPC was a function of the concentration of CPC in the feed solutions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.969-972
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• 1999

Nitrate is taken up from the soil by plants for protein synthesis and present in vegetables as a natural component and/or contaminant. The objective of this study was to estimate nitrate(NO3-) contents of some vegetables(Chinese cabbage, radish, lettuce, spinach) which were produced in Korea and to provide a scientific basis for the evaluation of risk to public health arising from dietary exposure to nitrate. A total of 400 samples were analysed for nitrate contents using our ion chromatography. From the results, in general, nitrate levels in vegetables produced by 2 harvest seasons were not different. The minimum, maximum and mean values of nitrate were 311, 5522 and 2788 for spinach; 542, 4484 and 2287 for lettuce; 273, 4151 and 1551 for radish; 362, 3015 and 1498(mg/kg) for Chinese cabbage. Nitrate contents of vegetables grown in Korea were similar to those of vegetables grown in other countries.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.192-195
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• 2003

As a part of our research project for in-situ bioremediation of nitrate contaminated. groundwater, screening studies to determine an effective electron donor (EO) and/or carbon source (CS) such as acetate, ethanol, formate, fumarate, lactate, and propionate were conducted. To evaluate the feasibility for the biological degradation of nitrate, soil microcosm studies using nitrate-contaminated soil and groundwater were performed. The nitrate removal percentage in the order from the highest to the lowest was: formate, fumarate, and ethanol > lactate > propionate. Essentially no nitrate consumption was observed In acetate-fed microcosms. The order of nitrate removal rate from the highest to lowest was fumarate, formate, lactate, ethanol, and propionate. These results suggest that fumarate and formate are promising EDs/CSs for in-situ bioremediation of nitrate - contaminated oxygenated groundwater.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.104-109
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• 2007

The amount of nitrate in the tobacco leaf has been shown to be correlated with the levels of alkaloids and nitrosamines. Also the nitrate content of the tobacco correlated closely with the smoke delivery of nitric oxide and tobacco-specific nitrosamines (TSNAs). These are related with the effect of the reconstituted tobacco leaf(Recon) using the tobacco stems. Adsorption process is gaining interest as one of the effective processes of advanced liquid treatment for liquid containing unnecessary materials. This study is focused on the evaluation of four anion exchangers, a cation exchanger and an activated carbon, as adsorbents for reduction of nitrate anion from Recon extract. In order to analyze the nitrate anion, the IC method used in this work was carried out with a Dionex ICS-2000 system. The effects of dosages of adsorbents and concentration of extract on the removal of nitrate anion were examined. Experimental results showed that for nitrate-anion exchanger, nitrate-cation exchanger and nitrate-activated carbon adsorption system, approximately 70 %, 10 %, and 4 % removal efficiencies were achieved at the Brix 10 and the 20 % addition. Although the activated carbon was little efficient for removal of nitrate ion, the removal of nicotine was very efficient at given conditions.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.1-5
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• 2008

Salt accumulation in soils of greenhouse due to the massive application of nitrogen fertilizers causes salt stress on the various crops, a serious problem in domestic agriculture. Since the majority of the salinity is nitrate, the excess nitrate should be removed; therefore, a bacterial strain having high capacity of nitrate uptake and identified as Enterobacter amnigenus GG0461 was isolated from the soils of greenhouse. Optimum conditions for the bacterial growth and nitrate uptake were investigated. GG0461 was able to grow without nitrate; however, nitrate facilitated the growth. The rate of nitrate uptake increased at alkaline pH and both growth and nitrate uptake were maximal at pH 8-9. When the initial pH of culture medium was increased to pH 8 or 9, it was decreased to neutral upon bacterial growth and nitrate uptake. These results imply that the major factor mediating bacterial nitrate uptake is a nitrate/proton antiporter. The fact was supported by the effect of nitrate addition in the absence of nitrate, since the addition of nitrate greatly increased the nitrate uptake and rapidly decreased pH of media.

• Journal of Plant Biotechnology
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• v.48 no.3
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• pp.124-130
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• 2021

Nitrate is an important nutrient and signaling molecule in plants that modulates the expression of many genes and regulates plant growth. In this study, we cover the research status of transcription factors related to the control of gene expression by nitrate signaling in higher plants. Nitrate reductase is a key enzyme in nitrogen assimilation, as it catalyzes the nitrate-to-nitrite reduction process in plants. A variety of factors, including nitrate, light, metabolites, phytohormones, low temperature, and drought, modulate the expression levels of nitrate reductase genes and nitrate reductase activity, which is consistent with the physiological role if. Recently, several transcription factors controlling the expression of nitrate reductase genes have been identified in higher plants. NODULE-INCEPTION-Like Proteins (NLPs) are transcription factors responsible for the nitrate-inducible expression of nitrate reductase genes. Since NLPs also control the nitrate-inducible expression of genes encoding the nitrate transporter, nitrite transporter, and nitrite reductase, the expression levels of nitrate reduction pathway-associated genes are coordinately modulated by NLPs in response to nitrate. Understanding the function of nitrate in plants will be useful to create crops with low nitrogen use.