• Korean journal of food and cookery science
• /
• v.16 no.2
• /
• pp.173-181
• /
• 2000

To understand the influences of NaCl concentration and fermentation temperature on the ripening process of low salt fermented squids, squid with 5%, 7% and 9% salt were fermented at 10$\^{C}$ and 20$\^{C}$. The result of the changes of volatile basic nitrogen and free amino acids during the fermentation of squids are as follows. As a result of the observations on the changes of physicochemical components during the fermentation process of the low-salted squids, all the pH, VBN and NH$_2$-N were increased and therefore the fermentation was promoted. Considering the changes of net components according to the fermentation, ATP (Adenosine triphosphate) and ADP (Adenosine diphosphate) lost and could not be detected among the nucleotides and their related compounds. Besides, AMP (Adenosine monophosphate) existed only in the initial stage and inosine, hypoxanthine were the main components of nucleotides and their related compounds. Nonvolatile organic acids are mainly lactic acid, acetic acid and also they occupied more than 80%. Seeing the composition of free amino acid, the major amino acids are proline, arginine, methionine, alanine and glutamic acid.

• Journal of Plant Biology
• /
• v.4 no.2
• /
• pp.51-61
• /
• 1961

In order to detect the way of absorption and metaboism of the urea it is sprayed on the surface of the leaves of sunflower. The sunflowers used in this study are grown in different conditions such that the one in nittogen aboundant and the other in nitrogen deficient soil, respectively. The urea-N, ammonia-N, amide-N, and 80% alcohol soluble-N in the leaves were quantitatively determined. All of the nitrogenous components measured are generally tended to increased with rising the concentration of urea except only amide-N at 24 hours after sprayed, and these were highly significances. It seemed that hydrolizing of urea into ammonia and carbon dixide and the assimilation of ammonia into other organic nitrogenous constituents were rapid in the young leaves than in the mature. It is interest that the amide content, in the young leaves and nitrogen defieient one were enhanced with the increasing concentration of urea, although in the mature leaves it did not show any change in the urea treatment. It is presumed that the assimilation rate of ammonia and the urease activity were lower in the matture leaves than in the young and nitrogen deficient leaves. No significance at 5% level showed all of the nitrogenous components except total nitrogen between nitrogen abundant and deficent leaves. Urea content was a high peak at first 12 hours, ammonia at 48 hours, and amide and alcohol soluble nitrogen at 96 hours, whence decrease4d the content of these constituents gradually. The total nitrogen content is not incrased obviously by only one time of urea spray in this study. When the concentration of urea was relatively high there appeared the wilting spots on t도 edge of leaves. As a whole, it seemed that sprayed urea was rapidly absorbed and taken part in nitrogen metabolism within relatively short period.

• Korean Journal of Veterinary Research
• /
• v.36 no.3
• /
• pp.743-745
• /
• 1996

Chemical components of bovine aqueous humor were analyzed. Significant levels of protein, urea nitrogen, creatinine, cholesterol, calcium and electrolytes including sodium, potassium and chloride were detected. The composition of bovine aqueous humor is similar to that of cerebrospinal fluids, rather than that of plasma. It was also found that there is no significant difference in most components between aqueous humor of Korean native cattle and that of Holstein-Friesian cattle.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.2
• /
• pp.187-194
• /
• 2007

In order to utilize different nitrogen sources and to survive in a situation of nitrogen limitation, microorganisms have developed sophisticated mechanisms to adapt their metabolism to a changing nitrogen supply. In this communication, the recent knowledge of nitrogen regulation in the amino acid producer Corynebacterium glutamicum is summarized. The core adaptations of C. glutamicum to nitrogen limitation on the level of transcription are controlled by the global regulator AmtR. Further components of the signal pathway are GlnK, a $P_{II}-type$ signal transduction protein, and GlnD. Mechanisms involved in nitrogen control in C. glutamicum regulating gene expression and protein activity are repression of transcription, protein-complex formation, protein modification by adenylylation, change of intracellular localization, and proteolysis.

• Asian Journal of Turfgrass Science
• /
• v.1 no.1
• /
• pp.18-29
• /
• 1987

This study was carried out to examine the effect of nitrogen application and clipping interval on the characteristics of several turf components of korean lawngrass for the basic data of lawn management. It was treated by Split plot design with three replications. The main plots were nitrogen levels with 0, 350, and 700kgN / ha, and the sub plots were clipping intervals with 10, 20, and 30 days The results obtained are summarized as follows ; 1. Increasing the rate of nitrogen fertilizer and frequent clipping increased tiller number of korean lawngrass and the maximum number of tillers obtained in October were recorded from 700kgN application and clipping treatment of 10 days interval. Meanwhile, treatment of 350kgN with 10 days clipping interval increased tillers much more than those of 700kgN with 20 and 30 days clipping intervals. 2. The average number of green leaves occurred during the growth period maximized by applying 700 kgN and clipping 10 days interval. 3. Increasing tiller numbers significantly decreased tops DM weight per tiller by clippng plants at interval of 10 and 20 days, irrespective of nitrogen applied, and with nil N, at the interval of 30 days. By applying 700kgN however, tops DM weight per tiller increased as the number of tillers increased consistently. 4. The highest tops DM weight was achieved from late August to early September by applying 350 and 700kgN. 5. During the growth period, nitrogen application increased unders(stolon+root) DM weight, and, at the same level of nitrogen applied, the increase in stolon DM weight enhanced by lengthening the clipping interval to 30 days. 6. Nitrogen efficiency to green leaves, stolon nodes and DM weight of root with high nitrogen was achieved as clipping interval was shortened.

• Journal of Veterinary Clinics
• /
• v.24 no.2
• /
• pp.119-124
• /
• 2007

Milk components analysis was carried out milk yield(MY), milk fat(MF), milk protein(MP), milk urea nitrogen(MUN), milk solid(MS), day of non-pregnant condition(DNPC), and days of primipara(DPRI) involved. Dairy farms were divided high, middle and low groups according to the standard records for milk components. Examination records were divided by farm, parity, year, season and month, the number of samples were 28,957. MUN concentration was below 12 mg and when the MPP was below 3.0%, the days of non-pregnant condition were $94{\pm}10.77$ days but concentration of MUN was under 12 mg and when MPP was above 3.2%, longer period of non-pregnant condtion of $181.3{\pm}9.25$ was noted. The days of gestation of the first calving cow was $495.9{\pm}9.04$ days when the concentration of MUN was below 12mg/dl and MPP was under 3.0%. If the concentration of MUN was 12 mg/dl and when the MPP was over 3.2%, the days of gestation were $511.0{\pm}8.36$ days. It was believed that the concentrations of MPP and MUN have significant effects on the days of non-pregnant condition and the days of gestation. Determination of MY, MF, MS, and MUN was Milkoscan $4,000{\sim}5,000$ Serier(FOSS Electric Co., Copenhagen, Denmark). MUN standard concentration was 12-18(mg/dl) similar to blood urea nitrogen(BUN). Mutual relationship of milk components(MF, SCC, MY, DNPC, MS) and MUN concentration was low in regression analysis.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.4
• /
• pp.479-484
• /
• 2004

The study was conducted to assess the effect of milk production, parity, stage of lactation, season and individual milk components themselves on milk urea nitrogen (MUN) concentration and other milk components of 3,219 Holstein dairy cows in Korean dairy farms. The MUN concentrations in Korean dairy cows were estimated to 16.68$\pm$5.87 mg/dl. Milk yield was negatively correlated with fat and protein contents and somatic cell counts (SCC) in milk (p<0.01). The increasing MUN concentration has positive correlation with yield and fat content. By increasing somatic cell, milk yield was reduced and MUN level was increased. Cows in spring and winter produced more milk over 1.43 and 0.93 kg/day, respectively, than cows in summer (p<0.01). Milk urea nitrogen concentrations of milk produced in summer and fall were significantly lower (p<0.01) than those in spring and winter. Both MUN concentration and somatic cell counts were highest in winter. Milk yield was lower (p<0.01) in the first calving than other calving time and was tended to increase until the fifth parity and then decrease. Milk urea nitrogen and SCC were not related to parity of cows in this study. Milk yield and SCC were positively related to lactation period while MUN concentrations and milk fat and protein contents were negatively influenced by stage of lactation. In the present study, the relationship between MUN and reproduction of dairy cows was also investigated. Cow produced milk in high MUN concentrations (greater than 18 mg/dl) had more open days than cows in MUN concentrations less than 18 mg/dl. However, no significant difference between MUN concentration levels and frequency of artificial insemination was found in this study. It is suggested that although MUN values for nutritional management and measures of production or reproduction are used, non-nutritional factors should be considered.

• Journal of Nutrition and Health
• /
• v.23 no.3
• /
• pp.179-186
• /
• 1990

Nitrogen(N) concentrations of human milk in various fractions, such as total, protein, nonprotein, whey protein and casein were determined at 2-3 days, 1, 2, 4, 6 and 12 weeks of postpartum. significant decreases in total N, nonprotein N, protein N, whey protein N and casein N were found with time postpartum. Total nitrogen decreased from 401mg/dl at 2-3 days to 211mg/dl at 12 week. Whey protein nitrogen was found to contribute to the total nitrogen decrease with time. The percentage of nonprotein nitrogen was 13% in colostrum and 17-18% in mature milk. The proportions of whey protein and casein nitrogen were 55:45 at 2-3 days and 34:66 at 12 week postpartum. These determinations will provide the basic information on the variability of nitrogen components as lactation proceed.

• Microbiology and Biotechnology Letters
• /
• v.23 no.1
• /
• pp.12-16
• /
• 1995

Medium components for lactic acid production were optimized with a strain of Lactobacillus sp., isolated by our Lab. Nitrogen source was the key component and manganese ion was also important for lactic acid production in this strain. Optimal concentration of manganese ion was 0.03 g/l as MnSO$_{4}$ 4 - 5 H$_{2}$O base. Other mineral elements, however, had little effect on it. Among the nitrogen sources we examined, yeast extract showed the highest productivity. Yeast extract, the exellent but very expensive medium component, could be partially replaced by soytone until 60% dry base with higher productivity, or by tryptone enforced with vitamines and nucleic acids. In order to replace yeast extract completely, we examined several inexpensive nitrogen sources and their enzymatic hydrolyzates. The hydrolyzate of vital wheat gluten was the best of them.

• Journal of the Korean Home Economics Association
• /
• v.23 no.2
• /
• pp.29-36
• /
• 1985

This experiment was conducted to investigate changes of the components in steamed and roasted green tea after 10 min, 20 min and 30 min of heat treatment of heat treatment at $110^{\circ}C$. Vitamin C and tannin were determined by spetrophotometry. Total nitrogen, water-soluble nitrogen and water-soluble non protein nitrogen were determined by Kjeldahl analysis system. Aromas were identified by gas chromatography. After heat treatment, contents of most compounds decreased. Tannin and caffeine decreased a little bit, while vitamin C decreased considerably. There were both decreases and increases in aromas. Aromas which increased were geraniol, trans-2-hexenol, linalool, $\alpha$-ionone and $\beta$-ionone. From these results, it was concluded that the highest quality of green tea was one steam- treated for 10 min at $110^{\circ}C$.