• Journal of the East Asian Society of Dietary Life
• /
• v.20 no.5
• /
• pp.680-686
• /
• 2010

Silk sericin protein was hydrolyzed by seven proteolytic enzymes in order to examine the effectiveness of the hydrolysates in binding calcium. The amino acid nitrogen content of hydrolysates from Flavourzyme was higher than that for other enzymes, and its calcium binding capacity showed a dose-dependent increase. We examined the effects of calcium binding peptide from sericin hydolysates on the bioavailability of Ca-deficient rats. Three-week-old male rats were fed an Ca-deficient diet for three weeks. Rats were divided into four groups (DD: non-treated group on calcium deficient diet; DD+MC: milk-calcium treated group; DD+OC: organic calcium made using sericin hydolysates; and DD+IC: inorganic calcium ($CaCl_2$). After oral administration of calcium supplements for one week, the calcium content of the serum and liver were significantly higher in DD+OC ($101.7{\mu}g$/mL and $49.3{\mu}g$/mL) and DD+MC ($83.6{\mu}g$/mL and $42.8{\mu}g$/mL) than DD ($86.3{\mu}g$/mL and $43.4{\mu}g$/mL). The alkaline phosphatase (ALP) content in the treated groups was significantly lower than DD, but no significant difference among groups was shown. Aspartate aminotransferase (AST) levels did not show any significant difference between groups. Alanine aminotransferase (ALT) levels were significantly reduced compared to the DD group. In conclusion, binding calcium to peptides from sericin hydrolysates seems to improve its bioavailability, and to hasten the cure of calcium deficiency in experimental rats.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.68 no.4
• /
• pp.276-284
• /
• 2023

Nitrogen is a major and essential macronutrient for plant growth and development. However, excessive nitrogen application can lead to ecological pollution or greenhouse gas emissions, consequently resulting in climate change. In this study, we used 153 genetic resources of rice to evaluate the effects of the levels of nitrogen application on grain yield and yield-related traits. Significant differences were noted in the yield and yield-related traits of genetic resources between two nitrogen application levels, namely, 4.5 kg/10a (NN: normal nitrogen condition) and 9.0 kg/10a (LN: low-nitrogen condition). Among the tested traits, days to heading (DTH), clum length (CL), grain yield per plant (GYP), number of panicles per plant (NPP), and number of spikelets per panicle (NSP) decreased by 1.8 to 17.9% when the nitrogen application levels decreased from NN to LN. The 1,000-grain weight (TWG) and percentage of ripened grain (PRG) increased by 2.6 to 11.2% under these conditions. Based on nitrogen application levels, two-way analysis of variance (ANOVA) demonstrated significant differences in GYP, NPP, and PRG but not in NSP and TGW. NPP exhibited negative correlations with NSP (-0.44) and TGW (-0.44), and TGW displayed a negative correlation with PRG (-0.34), whereas, GYP exhibited a positive correlation with PRG (0.37) and NSP (0.38). A similar pattern was recorded under the LN condition. NPP, TGW, and PRG were clustered as PA (principle axis) 1 under the LN condition by factor analysis. NSP and GYP were clustered as PA (principle axis) 2. These results demonstrated NPP and NSP as the primary factors contributing to the decrease in grain yield under LN conditions. In conclusion, we selected eight genetic resources that exhibited higher GYP under both NN and LN conditions with higher NPP or NSP. These genetic resources can be considered valuable breeding materials for the adaptation of plants to nitrogen deficiency.

• KSBB Journal
• /
• v.10 no.4
• /
• pp.349-356
• /
• 1995

To produce PHA(polyhydroxyalkanoic acid) from microbr, dozens of microorganism have been screened from sewage sludge. Selected a strain HJ out of 50 strains of PHA producing bacteria has a capability of accumulating large amounts of PHB/HV copolymer when grown in batch culture with a single carbon source (glucose) that was not generally considered as precursor of hydroxyvalerate monomer unit. The strain HJ was identified as the genus Pseudomonas with respect to morphological, cultural, and biochemical characteristics. The optimal temperature and pH for cell growth were $37^{\circ}C$ and 7.0. The optimal medium compositions for cell growth were glucose 1% as a carbon source, (NH4) 2SO4 0.2% as a nitrogen source, K2HPO4 0.3%, and KH2PO4 0.45%. TO investigate she optimal condition for PHA production two-step cultivation method was employed. PHA production was inducted by deficiency of NH4+, SO4-2, Mg+2. Besides carbon source, deficiency of all nutrients stimulated PHA productivity but deficiency of NH4+ stimulated the most HV monomer content. The highest PHA production was C/N molar ratio 95.2. Pseudomonas sp. HJ was also able to pyoduc PHB/HV copolymer when cultivated on alkane, alkanoate, alcohol as carbon sources. The contents of PHA and she proportions of hydroxyvalerate monomer units varied depending on the carbon sources. Especially Pseudomonas sp. HJ was able to incorporate hydroxyvalerate into PHB/HV to level as high as from 49 to 74 mol% when grown in a medium containing hexadecane and propionate. The purified PHA was identified PHB/HV copolymer by HNMR analysis.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.1
• /
• pp.13-21
• /
• 2004

Temporal changes of Chl-α, physical and chemical factors were investigated by diurnal observation at 2-hour interval at three fixed stations in the western Chinhae Bay from 12 Aug. to 13 Aug. 1999. Difference of dissolved oxygen between surface and bottom layer was maximum when the thermocline were strong. Organic distribution such as COD was affected by the growth of phytoplankton. Limitting factor was nitrogen, that is, inorganic nitrogen plays a significant role on regulating the algal growth. Surface distribution of dissolved inorganic nitrogen was very low compared to bottom layer by uptake of organisms. Maximum value of Chl-α at station C2 and C11 were observed from subsurface layer, ranges of which exceeded possibility concentration of red tide outbreak, 10 mg/㎥. On the other hand, that of C15 exist at surface layer. In this area, DIN and DIP concentrations increased by input sources such as rainfall and benthic flux before the bloom of phytoplankton. Accumulation of phytoplankton occurred at subsurface layer by the rapid uptake of DIN, especially nitrate ion, when strong thermocline existed as approach to the afternoon, which led to the increase of organics in water column and oxygen deficiency water mass at bottom layer until late at evening. Since then, DIN increases gradually as water temperature decrease to minimum. The quantitative understanding of nitrogen of fluxed to and from the various sources is necessary for environmental management.

• Korean Journal of Agricultural Science
• /
• v.51 no.2
• /
• pp.193-203
• /
• 2024

This study examined the effect of a dietary protein level and age on growth performance, total excreta, and nitrogen balance in laying hen during the growing period for 18 weeks. A total of 96 Hy-Line Brown laying hens were divided into two treatments according to the experimental diets, with each group consisting of six replicates. The experimental diets included: 1) an adequate metabolizable energy and crude protein diet formulated to meet the age and breed specification for Hy-Line Brown containing 21, 18, 16, and 14% dietary CP during 0 to 6, 6 to 12, 12 to 15, 15 to 18 weeks, respectively (CON); 2) 2% CP deficiency from CON diet containing 19, 16, 14, 12% dietary CP during 0 to 6, 6 to 12, 12 to 15, 15 to 18 weeks, respectively (LP). Growth performance, total excreta, and nitrogen balance were investigated for 18 weeks every 3 weeks, and two-way ANOVA was used for statistical analysis of data. The LP group had lower total excreta and N intake than CON group in the whole period of the experiment (p < 0.001). Moreover, birds in the LP group showed lower N excretion than the CON group (p < 0.05). However, the CON group exhibited higher BW, ADG than the LP group (p < 0.001). Application of low-protein diet to laying hens during the growing period reduced N excretion, which contribute to the sustainable development of the laying hen industry by minimizing environmental pollution.

• Journal of Environmental Science International
• /
• v.14 no.4
• /
• pp.397-404
• /
• 2005

In order to study the temporal variations of nutrients and chlorophyll-a in the Bottol Bada, three field observations were carried out on 20, 23 and 26 July, 2004. The low N:P values exhibit nitrogen deficiency during the periods of observation. This result is not representative of typical summer environment in the southern coast of Korea. The possible mechanisms are as follows: 1) The freshwater inflow was not sufficient for the supply of nitrogen because the total precipitation was 11.9 mm in July, 2004. This amount is no more than $5\%$ in normal precipitation in July. 2) There was an inflow of oceanic water under the subsurface into the Bottol Bada. Even though the oceanic water comprises more nutrients, it produces the stratification between the surface and the subsurface water and seems to prevent the supply of nutrinets to the surface layer. 3) The high chlorophyll-a concentration of $1.2 {\cal}ug/L$ was shown near the narrow channel between Gae-do and Geumo-do. This seems to be resulted from the inflow of water from Gamak Bay.

• Applied Biological Chemistry
• /
• v.16 no.1
• /
• pp.18-30
• /
• 1973

The flag and lower leaves (4th or 5th) of rice plant from the field of NPK simple trial and from three low productive area were analyzed in order to find out certain diagnostic criteria of nutritional status at harvest. 1. Nutrient contents in the leaves from no fertilizer, minus nutrient and fertilizer plots revealed each criterion for induced deficiency (severe deficient case induced by other nutrients), deficiency (below the critical concentration), insufficiency (hidden hunger region), sufficiency (luxuary consumption stage) and excess (harmful or toxic level). 2. Nitrogen contents for the above five status was less than 1.0%, 1.0 to 1.2, 1.2 to 1.6, 1.6 to 1.9 and greater than 1.9, respectively. 3. It was less than 0.3%, 0.3 to 0.4, 0.4 to 0.55 and greater than 0.55 for phosphorus $(P_2O_5)$ but excess level was not clear. 4. It was below 0.5%, 0.5 to 0.9, 0.9 to 1.2, 1.2 to 1.4 and above 1.4 for potassium. 5. It was below 4%, 4 to 6, 6 to 11 and above 11 for silicate $(SiO_2)$ and no excess was appeared. 6. Potassium in flag leaf seemed to crow out nitrogen to ear resulting better growth of ear by the inhibition of overgrowth of flag leaf. 7. Phosphorus accelerated the transport of Mg, Si, Mn and K in this order from lower leaf to flag, and retarded that of Ca and N in this order at flowering while potassium accelerated in the order of Mn, and Ca, and retarded in the order of Mg, Si, P and N at milky stage. 8. Transport acceleration index (TAI) expressed as (F_2L_1-F_1L_2)\;100/F_1L_1$ where F and L stand for other nutrient cotents in flag and lower leaf and subscripts indicate the rate of a nutrient applied, appears to be suitable for the effect of the nutrient on the translocation of others. 9. The content of silicate $(SiO_2)$ in the flag was lower than that of lower leaf in the early season cultivation indicating hinderance in translocation or absorption. It was reverse in the normal season cultivation. 10. The infection rate of Helminthosporium frequently occurred in the potassium deficient field seemed to be related more to silicate and nitrogen content than potassium in the flag leaf. 11. Deficiency of a nutrient occured simultaniously with deficiency of a few other ones. 12. Nutritional disorder under the field condition seems mainly to be attributed to macronutrients and the role of micronutrient appears to be none or secondary.

• Journal of Bio-Environment Control
• /
• v.31 no.4
• /
• pp.384-392
• /
• 2022

The objective of this study was to estimated nitrogen content and chlorophyll using RGB, Hyperspectral sensors to diagnose of nitrogen nutrition in apple tree leaves. Spectral data were acquired through image processing after shooting with high resolution RGB and hyperspectral sensor for two-year-old 'Hongro/M.9' apple. Growth data measured chlorophyll and leaf nitrogen content (LNC) immediately after shooting. The growth model was developed by using regression analysis (simple, multi, partial least squared) with growth data (chlorophyll, LNC) and spectral data (SPAD meter, color vegetation index, wavelength). As a result, chlorophyll and LNC showed a statistically significant difference according to nitrogen fertilizer level regardless of date. Leaf color became pale as the nutrients in the leaf were transferred to the fruit as over time. RGB sensor showed a statistically significant difference at the red wavelength regardless of the date. Also hyperspectral sensor showed a spectral difference depend on nitrogen fertilizer level for non-visible wavelength than visible wavelength at June 10th and July 14th. The estimation model performance of chlorophyll, LNC showed Partial least squared regression using hyperspectral data better than Simple and multiple linear regression using RGB data (Chlorophyll R²: 81%, LNC: 81%). The reason is that hyperspectral sensor has a narrow Full Half at Width Maximum (FWHM) and broad wavelength range (400-1,000 nm), so it is thought that the spectral analysis of crop was possible due to stress cause by nitrogen deficiency. In future study, it is thought that it will contribute to development of high quality and stable fruit production technology by diagnosis model of physiology and pest for all growth stage of tree using hyperspectral imagery.

• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.2
• /
• pp.79-87
• /
• 2009

Pot experiments using sand culture were conducted in 2004 under greenhouse conditions to evaluate the effect of nitrogen deficiency on red pepper biomass. Nitrogen stress was imposed by implementing 6 levels (40% to 140%) of N in Hoagland's nutrient solution for red pepper. Canopy reflectance measurements were made with hand held spectral sensors including $GreenSeeker^{TM}$, $Crop\;Circle^{TM}$, and $Field\;Scout^{TM}$ Chlorophyll meter, and a spectroradiometer as well as Minolta SPAD-502 chlorophyll meter. Canopy reflectance and dry weight of red pepper were measured at five growth stages, the 30th, 40th, 50th, 80th and 120th day after planting(DAT). Dry weight of red pepper affected by nitrogen stress showed large differences between maximum and minimum values at the 120th DAT ranged from 48.2 to $196.6g\;plant^{-1}$, respectively. Several reflectance indices obtained from $GreenSeeker^{TM}$, $Crop\;Circle^{TM}$ and Spectroradiometer including chlorophyll readings were compared for evaluation of red pepper biomass. The reflectance indices such as rNDVI, aNDVI and gNDVI by the $Crop\;Circle^{TM}$ sensor showed the highest correlation coefficient with dry weight of red pepper at the 40th, 50th, and 80th DAT, respectively. Also these reflectance indices at the same growth station was closely correlated with dry weight, yield, and nitrogen uptake of red pepper at the 120th DAT, especially showing the best correlation coefficient at the 80th DAT. From these result, the aNDVI at the 80th DAT can significantly explain for dry weight of red pepper at the 120th DAT as well as for application level of nitrogen fertilizer. Consequently ground remote sensing as a non-destructive real-time assessment of plant nitrogen status was thought to be a useful tool for in season nitrogen management for red pepper providing both spatial and temporal information.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.1
• /
• pp.83-85
• /
• 2012

The causes of blossom-end rot (BER) are still not understood clearly, although there was a lot of research on the development of BER over 100 years. This experiment was conducted to investigate the influence of Ca content of fruit on the incidence of BER in red pepper. BER affected fruits and healthy fruits had been harvested and the samples were divided into two parts, the upper and the lower, for chemical analysis to determine the content of mineral nutrients in the tissue. The content of nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg) was higher in the BER affected fruits and the difference of each nutrient content was revealed much larger in the lower part of the fruit but there were no significant differences in calcium content between the BER and the healthy fruits of red pepper, in this experiment. The results indicate that it is difficult to find a certain relation between the calcium content of the fruit and the occurrence of blossom-end rot.