• Journal of Plant Biology
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• 제34권4호
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• pp.283-288
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• 1991

This work was carried out to determined the effect of 2,4-dinitrophenol(DNP) on in vivo nitrate reductase activity in the root of 6 day old rye (Secale cereale L.) seedlings. The nitrate reductase activity in the roots of 6 day old rye seedlings pretreated with 0.5 mM DNP was higher than that of the control group in all the experimental conditions. The optimal concentration of KNO3 for maximum nitrate reductase activity was 10 mM in both control and treated group. The nitrate reductase activity in the treatment of 10 mM KNO3 gradually increased for 4 h in both groups, and then maintained constantly. The nitrate reductase activity occurred per hour was highest at 1 h in both groups, while it was declined by large degrees as time goes on. The daily pattern of nitrate reductase activity was gradually decreased in both groups with the passage of day. The optimal pH for this experiment and a previous paper (Kwon et al., 1991), it was determined that the nitrate reductase activity in both roots and shoots of rye seedlings was increased by the treatment of 0.5 mM DNP, and particulary in both groups, the nitrate reductase activity in the roots of rye seedlings was higher than that in shoots of them.

• Applied Biological Chemistry
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• 제45권3호
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• pp.129-133
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• 2002

키토산 분해물을 시금치와 상추에 살포하였을 때, nitrate 함량이 감소되었으며, 이러한 감소는 nitrate reductase 활성의 증가에 기인한 것으로 나타났다. 이에 따라 채소 중 질산염을 가장 많이 축적하는 채소 중 하나인 시금치의 nitrate reductase를 식물체내에 과량 발현시켜 질산염 축적을 줄이기 위한 연구를 수행하였다. 첫 단계로 시금치 mRNA로부터 RT-PCR을 이용하여 cDNA를 분리, 증폭하고 벡터에 클로닝하여 염기서열을 결정하였다. 시금치 nitrate reductase cDNA의 염기서열은 다른 식물체에서 분리된 nitrate reductase 유전자들과 상당히 높은 상동성($71{\sim}82%$)을 보였고, 이미 발표된 시금치 nitrate reductase cDNA의 염기서열과 비교하였을 때 단지 두 염기만이 달랐다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권1호
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• pp.32-37
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• 2006

In this study, we have purified and characterized the membrane bound nitrate reductase obtained from the denitrifying bacteria, Ochrobactrum anthropi SY509, which was isolated from soil samples. O. anthropi SY509 can grow in minimal medium using nitrate as a nitrogen source. We achieved an overall purification rate of 15-fold from the protein extracted from the membrane fraction, with a recovery of approximately 12% of activity. The enzyme exhibited its highest level of activity at pH 5.5, and the activity was increased up to $70^{\circ}C$. Periplasmic and cytochromic proteins, including nitrite and nitrous oxide reductase, were excluded during centrifugation and were verified using enzyme essay. Reduced methyl viologen was determined to be the most efficient electron donor among a variety of anionic and cationic dyestuffs, which could be also used as an electron donor with dimethyl dithionite. The effects of purification and storage conditions on the stability of enzyme were also investigated. The activity of the membranebound nitrate reductase was stably maintained for over 2 weeks in solution. To maintain the stability of enzyme, the cell was disrupted using sonication at low temperatures, and enzyme was extracted by hot water without any surfactant. The purified enzyme was stored in solution with no salt to prevent any significant losses in activity levels.

• International Journal of Industrial Entomology and Biomaterials
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• 제7권1호
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• pp.45-49
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• 2003

Foliar treatment with different concentrations of potassium chloride (KCl) to mulberry plants resulted in higher level of total chlorophyll, total sugars, soluble protein, in vivo nitrate reductase activity (NRA), net photosynthetic rate (NPR), pWUE and leaf yield. Optimal concentration was found to be 10.0 mM KCl with limited irrigation provided in the mulberry plantation planted in 90 ${times}$ 90 cm spacing. The deleterious effect of soil moisture stress condition has been found to be overcome by KCl foliar spray twice at 15 days interval. Regression and correlation coefficients were analyzed, and a strong positive correlation was found between chlorophyll and total sugars, soluble protein and in vivo nitrate reductase activity, leaf dry weight and net photosynthetic rate and pWUE and net photosynthetic rate.

• 아시안잔디학회지
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• 제1권1호
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• pp.69-74
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• 1987

This study was carried out to elucidate the seasonal changes of amylase an nitrate reductase activities in Zoysia japonica Steud. The seasonal changes of the amylase activity AA) in aboveground parts appeared high activity from the beginning of May to the beginning of July and in autumn showed an activity of rapid decreasing tendency. But, the AA in winter(Nov. 15~Feb 28 was not almost detected. The seasonal changes of nitrate reductase activity(NRA) in various organs appeared a very similar figures to the seasonal changes of AA. But, the NRA in the root was not almost detected.

• The Korean Journal of Ecology
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• 제15권1호
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• pp.9-18
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• 1992

Nitrate reductase activity(nra) were analysed in roots, stems and leaves plants in relation to different nitrogen sources and plastochron ages. Nra in roors and stems of soybean observed no differences in influence the nitrogen sources and plastochron ages, and the values showed to be only 5% of NRA in leaves. On the other hand,NRA in the leaves showed different result to nitrgen sources and plastochron ages. When the plants were less than PI6.0, NRA in leaves had being proportional to the concentration of nitrate and distingush decreased with an increasing plastochron age. At the later stage, upper than PI 8.0, the actvity had not effect to nitrate and plastochron ages. These results indicated that nitrate reduction in soybean was in early leaves.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권2호
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• pp.112-116
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• 2002

Effects of artificial electron donors to deliver reducing power on enzymic denitrification were investigated using nitrate reductase and nitrite reductase obtained from Ochrobactrum antroyi. The activity of nitrite reductase in the soluble portion was almost the same as that in the precipitated portion of the cell extract. Nitrate removal efficiency was higher with benzyl viologen than with methyl viologen or NADH as an artificial electron donor. The turn-over numbers of nitrate and nitrite reductase were 14.1 and 1.9 umol of nitrogen reduced/min$.$mg cell extracts, respectively when benzyl viologen was used as an electron donor.

• 한국환경농학회지
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• 제20권5호
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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.

• 한국환경농학회지
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• 제15권3호
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• pp.383-390
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• 1996

무의 재배시 사용되는 질소비료의 형태, 시비량, 제초제농도가 무의 부위별 질산태질소의 함량, 질산 환원효소 활성 및 생육에 미치는 영향을 조사한 결과는 다음과 같다. 1. 질산태 질소비료가 암모니아태 질소비료 보다 무의 생육에 더 효과적이었으며, 질산태질소의 함량의 경우 무의 엽병과 엽에서는 파종후 25일경에, 뿌리에서는 32일${\sim}$39일 사이에서 높게 나타났다. 2. 또한 무의 부위별 질산태질소 함량은 엽병, 뿌리, 그리고 엽의 순서로, 질산환원효소 활성은 엽병, 엽, 그리고 뿌리순서로 높게 나타났다. 제초제 Alachlor의 농도가 증가함에 따라 무에서의 질산태질소 함량이 증가하는 경향이었으며, 질산환원효소 활성도 같은 경향이었다.

• 생명과학회지
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• 제10권1호
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• pp.52-60
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• 2000

Up to now, there have been done much efforts in regard to nitrate reductase activity (NRA) of dicotyledonous herbs and important crop monocotyledons, but few to wild plants having canopy structure such as Carex. The objective of the present study are to determine: a) the optimum in vivo NR assay conditions for leaf samples of Carex species, b) changes of NRA according to section within leaf and leaf ages, c) diurnal variations. Optimized assay media of each Carex species were determined. NRA of C. rostrata adapted to oligotrophic habitats is readily saturated at lower substrate concentration than those of C. distans and C. gracilis, adapted to meso- and eutrophic habitats, respectively. All Carex species investigated have higher NRA in leaves than in roots. NRA of all species showed maximal values at the middle section of each leaf and in the youngest fully expanded leaves. Compared to C. gracilis, NR in leaves of C. distans was adapted readily to the light period. On the whole, Carex showed rather delayed diurnal variation. Even if the in vivo nitrate reductase assay based on nitrite estimation does not give an accurate estimation of total nitrate reduced, it still serves as a useful tool to find out relative differences in varying environmental conditions. Additionally, in vivo RNA measurements are helpful to understand nitrate reduction and basic nitrogen metabolism of Carex species having different canopy structure.