• BMB Reports
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• 제56권2호
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• pp.56-64
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• 2023

Nitrogen (N) is an essential macronutrient required for plant growth and crop production. However, N in soil is usually insufficient for plant growth. Thus, chemical N fertilizer has been extensively used to increase crop production. Due to negative effects of N rich fertilizer on the environment, improving N usage has been a major issue in the field of plant science to achieve sustainable production of crops. For that reason, many efforts have been made to elucidate how plants regulate N uptake and utilization according to their surrounding habitat over the last 30 years. Here, we provide recent advances focusing on regulation of N uptake, allocation of N by N transporting system, and signaling pathway controlling N responses in plants.

• 한국해양바이오학회지
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• 제8권2호
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• pp.45-53
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• 2016

Most of microalgae shift their metabolic pathways toward the fatty acid biosynthesis following nitrogen deprivation. Recent studies on Nannochloropsis species, oleaginous microalgae, have been performed to investigate the regulation of contents and compositions of fatty acids under stressful condition. The objective of this experiment is to identify the effect of nitrogen on cell growth and fatty acids production in Nannochloropsis oculata K-1281 and compare fatty acid composition response to nitrogen deficiency between N. oculata LB2164 and K-1281. The fatty acids content in N. oculata K-1281 was increased up to 210%, while the growth rate was decreased under nitrogen deficient condition. The contents of C16:0 and C16:1 increased dramatically in both N. oculata K-1281 and LB2164, while the contents of C20:4 and C20:5 increased in N. oculata LB2164. The fatty acids content and composition in N. oculata K-1281 returned following addition of nitrogen after nitrogen starvation. These results demonstrated that fatty acid contents and compositions under nitrogen deficiency will provide the understanding of fatty acid synthesis in microalgae.

• Molecules and Cells
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• 제37권3호
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• pp.234-240
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• 2014

Cisplatin is one of the most potent chemotherapy agents. However, its use is limited due to its toxicity in normal tissues, including the kidney and ear. In particular, nephrotoxicity induced by cisplatin is closely associated with oxidative stress and inflammation. Heme oxygenase-1(HO-1), the rate-limiting enzyme in the heme metabolism, has been implicated in a various cellular processes, such as inflammatory injury and anti-oxidant/oxidant homeostasis. Capsaicin is reported to have therapeutic potential in cisplatin-induced renal failures. However, the mechanisms underlying its protective effects on cisplatin-induced nephrotoxicity remain largely unknown. Herein, we demonstrated that administration of capsaicin ameliorates cisplatin-induced renal dysfunction by assessing the levels of serum creatinine and blood urea nitrogen (BUN) as well as tissue histology. In addition, capsaicin treatment attenuates the expression of inflammatory mediators and oxidative stress markers for renal damage. We also found that capsaicin induces HO-1 expression in kidney tissues and HK-2 cells. Notably, the protective effects of capsaicin were completely abrogated by treatment with either the HO inhibitor ZnPP IX or HO-1 knockdown in HK-2 cells. These results suggest that capsaicin has protective effects against cisplatin-induced renal dysfunction through induction of HO-1 as well as inhibition oxidative stress and inflammation.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.179-185
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• 2001

Nitrate grown cells of cyanobacterium Plectonema boryanum, transferred to nitrogen stress, evolved nitrogenase catalyzed $H_2$ under microaerophilic condition. Nitrogen ($N_2$) in gs phase, low light intensity, and reducing substances in incubation phase stimulated $N_2$fixation ($H_2\;evolution$). Cyanobacterium grew slowly under microaerobic condition with a low intracellular ammonia pool. Nitrogen sources (${NO_3}^-,{NH_4}^+,\;and\;CH_3NH_3$) inhibited nitrogenase and glutamine synthetase (GS) transferase activity, and methylamine behaved like an ammonical nitrogen source. Depletion of molybdenum (Mo) and addition of tungsten (W) in the incubation medium inhibited $H_2$ evolution, Cyanobacterium was able to take up nitrate and expressed nitrate reductase (NR) activity under microaerophilic condition at an extremely slow rate.

• 수산해양교육연구
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• 제26권4호
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• pp.823-830
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• 2014

This study conducted to investigate the quality of commercial fish sauce and determine the grade of them by measuring the chemical compositions and biogenic amines. The commercial salt-fermented anchovy sauce contained 65.84-70.94% (mean : 68.39%) of moisture, 22.19-25.43% (24.22%) of salinity, 5.4-6.1 (5.8) of pH, 0.76-1.61%(1.18%) of total nitrogen, 478.52-924.66 mg/100 g (702.05 mg/100 g) of amino nitrogen and 584.59-1593.52 mg/kg of histamine. Whereas commercial salted-fermented sand lance sauces contained 66.63-71.99% (68.73%) of moisture, 23.9-25.5% (24.57%) of salinity, 5.5-6.4(6.16) of pH, 0.64-1.46% (1.07%) of total nitrogen, 433.51-1006.67 mg/100 g (665.36 mg/100 g) of amino nitrogen and 194.01-1839.68 mg/kg of histamine. Correlation of TN, AN and VBN containing nitrogen was high, but there was no significant correlation between these results and histamine. In total nitrogen content, 6 of the 20 fish sauces were less than Korea Food Standard. The eight samples were less than the amino nitrogen regulation of Korean Industrial Standard (KS). And 14 fish sauce were exceeded by 68% for moisture content standard of Korean Industrial Standard.

• 미생물학회지
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• 제26권2호
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• pp.93-100
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• 1988

In order to understand the regulation of glutamate dehydrogenase(GDH) synthesis in Brevibacterium flavum, we have isolated a mutant lacking NADP-linked GDH activity by ethlmethane sulfonate treatment. The $gdh^-$ mutant was grown on the minimal plate with 1mM ammonium chloride and not that with 300mM ammonium chloride. The cell-free extracts from $gdh^-$ mutant and prototroph were also examined with glutamine synthetase(GS) and glutamate synthase (GOGAT) production by niteogen sources. The growth of $gdh^-$ mutant in presence of 20mM ammonium chloride means that GOGAT synthesis is sufficient to allow growth in this condition. GS production of $gdh^-$ mutant as well as parental strain was induced by 1mM urea and ammonium tartrate, but it was repressed by higher concentration of ammonia, and also induced by 20mM to 50mM glutamate as a substrate. It was special attention that GOGAT synthesis from $gdh^-$ strain was more repressed by higher concentration of ammonia than prototroph as described in E. coli system.

• 한국기계가공학회지
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• 제10권5호
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• pp.79-84
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• 2011

Air pollutants from a small marine diesel engine are increasing and the IMO(International Marine Organization) regulation asked for its reduction. In this study, NOx reduction technologies such as improvement of various cooling systems are applied to the small marine diesel engine. The various cooling systems are a intercooler, a heat exchanger for engine coolant, and an exhaust manifold by water cooling. These systems are tested on an engine dynamometer and a exhaust gas analyzer by a marine diesel engine test regulation. Test results are shows that the small marine engine are satisfied the IMO NOx regulations; Tire II.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.152-157
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• 2006

The air pollutant emission from the railroad diesel locomotive is still a significant environmental concern in many countries including Korea and Unites States. The emission characteristics of the railroad diesel locomotive were extensively studied in this study. Particulate matter (PM) and nitrogen oxides ($NO_x$) emitted from a large locomotive engine (2-cycle, 16-cylinder, and 3,000-horsepower) under various engine-rating conditions was analyzed with a scanning mobility particle sizer and a gas stack sampler by using a dilution tunnel. We could gain the emission values of 2.1 g/horsepower-hour for PM and 42.7 g/horsepower-hour for $NO_x$. We proposed the emission reduction goal of the railroad diesel locomotive for Korea in comparison with the regulation of United States.

• BMB Reports
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• 제35권5호
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• pp.443-451
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• 2002

Malonate is a three-carbon dicarboxylic acid. It is well known as a competitive inhibitor of succinate dehydrogenase. It occurs naturally in biological systems, such as legumes and developing rat brains, which indicates that it may play an important role in symbiotic nitrogen metabolism and brain development. Recently, enzymes that are related to malonate metabolism were discovered and characterized. The genes that encode the enzymes were isolated, and the regulation of their expression was also studied. The mutant bacteria, in which the malonate-metabolizing gene was deleted, lost its primary function, symbiosis, between Rhizobium leguminosarium bv trifolii and clover. This suggests that malonate metabolism is essential in symbiotic nitrogen metabolism, at least in clover nodules. In addition to these, the genes matB and matC have been successfully used for generation of the industrial strain of Streptomyces for the production of antibiotics.

• 한국균학회지
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• 제18권4호
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• pp.181-190
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• 1990

The growth and biochemical activities of Chlorella fusca were studied in the presence of different concentrations of either filtrates or mycelial mats of Saprolegnia ferax and Pythium graminicola. Low concentrations of both fungal filtrates exerted increase in total count, dry weight and in the biosynthesis of photosynthetic pigments, carbohydrates and nitrogen content. High concentrations showed inhibitory effect on both growth and biochemical activities of Chlorella fusca. Supplementation with different concentrations of dry mycelial mats of either fungi the culture of Chlorella showed elevation in biomass, dry weight, and biosynthesis of carbohydrates and nitrogen content especially at low concentrations. The contents of photosynthetic pigment were inhibited only at low concentrations. Neither the culture filtrate of Pythium nor Saprolegnia had cellulolytic activity, although polygalacturonase enzymes were detected, whereas chloroform-extract of both fungal filtrates showed blue spots under long wave light (366 nm).