• Journal of Nutrition and Health
• /
• v.10 no.4
• /
• pp.111-115
• /
• 1977

Vegetables and fruits purchased from several markets in Seoul from July to October in 1977 were analyzed to know the level of nitrate-and nitrite-nitrogen accumulation in relation to a public health. Radishes and chinese cabbages utilized mainly as pickled vegetables in Korea resulted in the highest concentration of nitrate-nitrogen. Some of the levels for radishes and chinese cabbages were notably high and exceeded a recommended upper limit of 300 ppm $No_{3}-N$, and thus these levels would render these samples unsafe for use. The levels in some of vegetables other than radish and chinese cabbage, e.g., spinach, lettuce, green onion, cabbage were relatively high and considered to be unsafe for use in feeding infants, where as those of green pepper, bean sprouts and parsely were very low and safe. And also the levells in fruits were very low and safe. Nitrite-nitrogen contents in all tested vegetables and fruits ranged to trace and appeared not to be accumulated in fresh vegetables and fruits. Stems and roots of radishes and chinese cabbages accumulated approximately 2 fold more nitrate-nitrogen than leaves in 5 samples of each vegetable tested.

• KSBB Journal
• /
• v.24 no.2
• /
• pp.195-200
• /
• 2009

The effect of nitrogen source on cell growth and benzo[c]phenanthridine alkaloids production by modifying $NO_3\;^-:NH_4\;^+$ ratio in cell suspension culture of Eschscholtzia califarnica was investigated. When total nitrogen concentration is maintained (60 mM), maximum benzo[c]phenanthridine alkaloids production is about 60.72 mg/L at 50:10 (mol/mol). This productivity was 3.8 times higher than that obtained when cells were grown instandard MS medium. The decrease of $NO_3\;^-:NH_4\;^+$ ratio at 60 mM of total nitrogen caused the decline of both growth and benzo[c]phenanthridine alkaloids production. Under the same concentration of $N0_3\;^-$ (50 mM), higher concentration of $NH_4\;^+$ inhibited cell growth strongly but induced alkaloids production slightly. Also, under the same concentration of $NH_4\;^+$ (25 mM), higher concentration of $N0_3\;^-$ induced alkaloids production strongly but high concentration of $N0_3\;^-$ (${\geq}$100 mM) interfered alkaloids instead. Maximum benzo[c]phenanthridine alkaloids production is about 62.71 mg/L at 50:25 (mol/mol). These results suggest that higher biomass and higher alkaloids production could be obtained by optimizing each nitrogen concentration as well as $NO_3\;^-:NH_4\;^+$ ratio in the culture medium. Nitrate and ammonium in culture medium have distinct role in the regulation of growth and alkaloids production; ammonium had a strong influence on growth while nitrate had an influence on alkaloids production.

• Korean Journal Plant Pathology
• /
• v.1 no.1
• /
• pp.44-50
• /
• 1985

Effect of nitrogen sources on mycelial growth and sclerotial formation of Rhizoctonia solani causing rice sheath blight was studied by using sixty isolates from diseased samples of different localities in Chungbuk area. Based on the cultural characters, pathogenicity and sclerotial formation, three isolates of the fungus were selected. The virulence of the three isolates varied based on the percent of seeds germination, seedling blights and length and lesion number of lesions. As nitrogen sources, arginine, alanine, urea, ammonium sulfate and sodium nitrate were more effective for mycelial growth and sclerotial formation, than were cystine, methionine, lysine, histidine, tryptophan and thyrosine. The mycelium of R. so/ani grew well in a lower concentration of urea, sodium nitrate, arginine, ammonium sulfate and lysine, but in a higher concentration of proline, histidine, and alanine. In all nitrogen sources tested, high concentration of nitrogen nutrients greatly stimulated sclerotial formation of the fungus. Arginine, urea, and ammonium sulfate increased virulence of the fungus. All the isolates grown on the basic medium plus proline produced large sclerotia. Mycelial growth of the fungus was not well in the tryptophan-added medium, showing brown discoloration of medium.

• Korean Journal of Plant Tissue Culture
• /
• v.25 no.1
• /
• pp.57-61
• /
• 1998

Soybean and tobacco tissue cultured with modified MS media containing 4 different ratio(as N) of nitrate to ammonium combination which were 3:0, 2:1, 1:2 and 0:3. The highest callus growth in soybean were observed in the 2:1 medium. The medium containing nitrate only was detrimental to soybean callus growth. Tobacco callus grown with nitrate-only grew as well as those in the 2:1 and very slowly with ammonium-only. In tobacco callus, the total nitrogen in the callus increased with the increase of nitrogen concentration in the medium, but in soybean callus, the opposite result was noted. Nitrate reductase activity in tobacco callus was high when grown with nitrate-only but low with ammonium-only. In case of soybean callus, nitrate reductase activity was high in the 2:1 and remarkably low in nitrate-only medium. Both in soybean and tobacco callus, the activity of glutamine synthetase was high with nitrate-only, but low with ammonium.

• Journal of Applied Biological Chemistry
• /
• v.48 no.1
• /
• pp.11-15
• /
• 2005

Salinity of soils in greenhouse has been increased by massive application of fertilizers. Nitrogen fertilizer was most popular, and thus nitrate became the majority of soil salinity. Accumulation of nitrate led to deleterious effects on the growth and development of crops and vegetables. Microbial strains able to utilize nitrate and thus remove excess nitrate from farm land soils were isolated from 15 different soils of greenhouses and plastic film houses. Four strains able to grow in medium containing 50 mM $KNO_3$ were isolated, among which only E0461 showed high capacity of nitrate uptake. Nitrate uptake by E0461 was dependent on culture medium and was increased by addition of tryptone and peptone. Although E0461 was able to grow without tryptone and peptone, growth was slow, and no nitrate uptake was observed. Nitrate appeared to facilitate E0461 growth in the presence of tryptone and peptone. Through kinetic analysis, nitrate uptake was measured at various concentrations of nitrate, and half-life was calculated. Nitrate concentration decreased with increasing incubation period, and plot between half-lives and initial concentrations of nitrate fitted to single exponential function. These results suggest one major factor plays an important role in microbial nitrate uptake.

• Asian Journal of Turfgrass Science
• /
• v.5 no.1
• /
• pp.1-10
• /
• 1991

The purpose of the experiment was to determine the effect of nitrogen sources (urea, ammonium sulphate, ammonium nitrate) and potassium sources (potassium chloride, potassium sulphate) on the growth and quality of Zoysia japonica Steud. This experiment was conducted at Seoul City University turf field from 1988 to 1989. The results of this experiment were summarized as follows; 1. Urea and Ammonium sulphate resulted in superior clipping yield compared to ammonium nitrate. The growth of rhizome and stolon increased significantly with urea forms, but ammonium sulphate treated plots exhibited the highest the growth rate of root. 2. Ammonium sulphate showed best turf color rating while ammonium nitrate resulted in the poorest. Prolongation of the green period showed longer in ammonium sulphate and urea treated plots than ammoium nitrate. 3. Urea and ammonium sulphate exhibited superior visible quality and shoot density compared to ammonium nitrate. 4. The uptake of mineral nutrient showed the highest concentration with urea plots. Surface soil pH was allowed to become slightly acid with the ammonium sulphate and potassium sulphate treatments, while the application of N and K sources did not cause significant differences in mineral element content in soil.

• Applied Biological Chemistry
• /
• v.38 no.4
• /
• pp.308-312
• /
• 1995

The effects of nitrogen, phosphate in modified B5 medium and cell immobilization on cell growth and taxol production were investigated using cell cultures of Taxus cuspidata. The ratio of nitrate to ammonium was found to be an important parameter. The ratio of 1 increased taxol production 10-fold, compared to the original ratio of 20 in modified B5 medium. Reducing phosphate concentration inhibited cell growth, but increased taxol production noticeably. Immobilized cells produced a taxol concentration of ${\sim}120\;g/l$

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.4
• /
• pp.606-613
• /
• 1997

The changes of contents in trimethylamine oxide nitrogen(TMAO-N), trimethylamine nitrogen(TMA-N), dimethylamine nitrogen(DMA-N), nitrite nitrogen(nitrite-N), nitrate nitrogen(nitrate-N) and the effect on the formation of N-nitrosamine(NA) during fermentation were investigated with salted anchovy added different amounts of sodium nitrite, sodium nitrate and ascorbic acid, respectively. When the sodium nitrite was added in salted anchovy, the contents of nitrite-N was decreased during fermentation . Whereas the formation of N-nitrosodimethylamine(NDMA ) was increased . Contents of TMAO-N was decreased, while TMA-N and DMA-N were increased during fermentation in all samples. Addition of ascorbic acid inhibited the formation of NDMA significantly. The formation of NDMA was inhibited by 81.3% at the concentration of 130mM as compared with non-added the control group. The aqueous model system was used for the evaluation of ascorbic acid(inhibitor) or thiocyanate (promoter) on the formation of NDMA using salt-fermented anchovy added with sodium nitrite. The optimum pH on the formation of NDMA was shown to be 3.8, and ascorbic acid inhibited the formation of NDMA whereas thiocyanate promoted. NDMA was not detected in the salt-fermented anchovy (control sample). However it is a possibility to form carcinogenic NDMA in stomach if both saltfer-mented anchovy and the materials contained abundant nitrite or nitrate were took in.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.8
• /
• pp.1235-1243
• /
• 2020

The use of microalgal biomass as feedstock for biofuels has been discussed for decades as it provides a sustainable approach to producing fuels for the future. Nonetheless, its feasibility has not been established yet and various aspects of biomass applications such as CO₂ biofixation should also be explored. Therefore, in this study, the CO₂ biofixation and lipid/carbohydrate production potential of Chlorella sp. ABC-001 were examined under various nitrogen concentrations. The highest biomass productivity and CO₂ biofixation rate of 0.422 g/l/d and 0.683 g/l/d, respectively, were achieved under a nitrogen-rich condition (15 mM nitrate). Carbohydrate content was generally proportional to initial nitrate concentration and showed the highest value of 41.5% with 15 mM. However, lipid content showed an inverse relationship with nitrogen supplementation and showed the highest value of 47.4% with 2.5 mM. In consideration as feedstock for biofuels (bioethanol, biodiesel, and biogas), the sum of carbohydrate and lipid contents were examined and the highest value of 79.6% was achieved under low nitrogen condition (2.5 mM). For lipid-based biofuel production, low nitrogen supplementation should be pursued. However, considering the lower feasibility of biodiesel, pursuing CO₂ biofixation and the production of carbohydrate-based fuels under nitrogen-rich condition might be more rational. Thus, nitrogen status as a cultivation strategy must be optimized according to the objective, and this was confirmed with the promising alga Chlorella sp. ABC-001.

• Journal of Environmental Health Sciences
• /
• v.46 no.6
• /
• pp.646-654
• /
• 2020

Objectives: Users of parks or children's play facilities have pointed to pets' bowel movements as the most serious problem when using them. In prior studies, a very low detection rate of parasites (eggs) in sand flooring materials has been found. Even though feces have been identified, no parasites (eggs) have been detected. Method: A standard solution of nitrate nitrogen was used to verify the reliability of a new nitrogen analysis method. The linearity, precision, and accuracy of the nitrate nitrogen analysis method were verified. Using this method, the pollution distribution of the sand flooring material and the degree of pollution at each point were investigated. Results: As a result of the verification of the nitrogen analysis method, the linearity was found to be good at r2=0.999 when distilled water is mixed in a standard substance solution. The standard substance additive solution r2=0.968 was found to be good. Precision represented 0.01 to 0.06% RSD for peak height. The recovery rate was 92.4 to 104.0 percent, indicating high accuracy. According to the same method of analysis, the flooring material sand at a general amusement facility with the largest number of concealed spaces was nitrate nitrogen 6.1 times higher than at the entrance of the playground. Also, in a comparison between clean sand and sandy flooring, the average nitrogen concentration of the sand flooring material was 24.4-167 times higher than pure sand. Conclusions: As such, no parasites (eggs) were detected at all points under investigation, but the sand flooring was exposed to animal fecal contamination. Therefore, the management of nitrogenous components should allow accurate identification of animal fecal contamination so that the timing of sand replacement can be managed hygienically and safely.