• Korean Journal of Microbiology
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• v.29 no.4
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• pp.258-262
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• 1991

Rate of 11.alpha.-hydroxylation of progesterone with Rhizopus nigricans was accelerated by glucose. Glucose seemed to play an important role in the formation of cofactor because its effects on the reaction were almost same as those of electron acceptors such as NADPH and $NaIO_{4}$. Rate of glucose consumption appeared to increase in proportion as the rate of hydroxylation reaction, which enhanced with increase in the glucose concentration to level off at 0.5 g/l for mycelia and at 20 g/l for spores. However, for mycelia immobilized in polyacrylamide gel, externally added glucose did not affect the reaction rate at all because of the glucose accumulated in the gel during the cultivation period. 5.alpha.-Reduction of 11.alpha.-hydroxyprogesternoe required much higher concentration of glucose than 11.alpha.-hydroxylation of progesternoe so that high yield of 11.alpha.-hydroxyprogesternoe can be obtained by repressing the activity of 5.alpha.-reductase at low concentration of glucose.

• Molecules and Cells
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• v.21 no.1
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• pp.112-120
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• 2006

It has been suggested that defective interfering (DI) RNA contributes to the persistence of Japanese encephalitis virus (JEV). In this study, we characterized molecular and biological aspects of the DI RNA and its relation to viral persistence. We identified a homologous DI virus intimately associated with JEV persistence in Vero cells. The production of DI RNA during undiluted serial passages of JEV coincided with the appearance of cells refractory to acute infection with JEV. We also established a Vero cell clone with a persistent JEV infection in which the DI RNA coreplicated efficiently at the expense of helper virus. The infectious virus yield of the clone fluctuated during its growth depending upon the amount of DI RNA accumulated in the previous replication cycle. Identification of the corresponding negative-sense RNA of the DI RNA indicated that the DI RNA functioned as a replication unit. Most of the DI RNA molecules retained their open reading frames despite a large deletion, encompassing most of the prM, the entire E, and the 5' half of the NS1 gene. Taken together, these observations suggest that the generation of homologous DI RNA during successive JEV acute infections in Vero cells probably participates actively in persistent JEV infection.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.233-239
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• 2015

Monitoring of soil fertility and crop productivity in long-term application of fertilizers is necessary to use fertilizers efficiently. This study was conducted to investigate effects of continuous application of lime for rice cultivation from 1969 to 2014. The treatments were no lime treatments (N, NPK, NPKC, and NPKS) and lime treatments (N+L, NPK+L, NPKC+L, and NPKS+L). The application of lime in addition to N, NPK, and NPKC tended to increase pH, exchangeable Ca, and available $SiO_2$. The input of mean annual $1,170Mg\;ha^{-1}yr^{-1}$ of lime increased pH $0.0042yr^{-1}$, $0.0062yr^{-1}$, $0.0127yr^{-1}$, and $0.0041yr^{-1}$ in lime treatments (N+L, NPK+L, NPKS+L, and NPKC+L) compared with no treatments (N, NPK, NPKS, and NPKC), respectively. The mean annual Ca field balance varied from 169 to $561kg\;ha^{-1}yr^{-1}$in no treatments, from 871 to $1,263kg\;ha^{-1}yr^{-1}$ in lime treatments, indicating that Ca was accumulated in the soils. The mean annual Ca field balance in silicate fertilizer treatments (NPKS, NPKS+L) were higher than that of other treatments because silicate fertilizer included Ca component. Grain yield of rice had no significant differences between no lime treatments and lime treatments. Thus the application of lime led to changes in soil chemical properties but had no impact on the production of rice.

• Journal of Microbiology and Biotechnology
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• v.31 no.6
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• pp.823-832
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• 2021

Mushroom cultivation along with the palm oil industry in Malaysia have contributed to large volumes of accumulated lignocellulosic residues that cause serious environmental pollution when these agroresidues are burned. In this study, we illustrated the utilization of lignocellulolytic enzymes from the spent mushroom substrate of Pleurotus pulmonarius for the hydrolysis of palm oil mill effluent (POME). The hydrolysate was used for the production of biohydrogen gas and enzyme assays were carried out to determine the productivities/activities of lignin peroxidase, laccase, xylanase, endoglucanase and β-glucosidase in spent mushroom substrate. Further, the enzyme cocktails were concentrated for the hydrolysis of POME. Central composite design of response surface methodology was performed to examine the effects of enzyme loading, incubation time and pH on the reducing sugar yield. Productivities of the enzymes for xylanase, laccase, endoglucanase, lignin peroxidase and β-glucosidase were 2.3, 4.1, 14.6, 214.1, and 915.4 U g^-1, respectively. A maximum of 3.75 g/lof reducing sugar was obtained under optimized conditions of 15 h incubation time with 10% enzyme loading (v/v) at a pH of 4.8, which was consistent with the predicted reducing sugar concentration (3.76 g/l). The biohydrogen cumulative volume (302.78 ml H₂.L^-1 POME) and 83.52% biohydrogen gas were recorded using batch fermentation which indicated that the enzymes of spent mushroom substrate can be utilized for hydrolysis of POME.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.206-217
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• 1982

This experiment was conducted to study about nutrient absorption of flag leaf and chaff of rice plant different transplanting date with elevations. Heading stage was delayed by destructive cold temperature or late transplanting. Plant analyses revealed that above poor plants also had higher total nitrogen content, but ower silicate in the flag leaf and sterile chaff. Total nitrogen and silica contents to accumulated in flag leaf between yield was significant high correlation. The chaff of late transplanting and sterility was high total nitrogen. Relationship between silicate absorption and total nitrogen of chaff was significant high correlation. Ripening temperature after heading stage was influenced total nitrogen of chaff. Phosphate, potassium, calssium and silicate contents of chaff increased hight ripening temperature but total nitrogen decreased. Therefore, inorganic element contents of chaff was closely connected with grain sterility.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.939-950
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• 2023

This study was conducted to assess the impact of growing condition variables on alfalfa (Medicago sativa L.) productivity. A total of 197 alfalfa yield results were acquired from the alfalfa field trials conducted by the South Korean National Agricultural Cooperative Federation or Rural Development Administration between 1983 and 2008. The corresponding climate and soil data were collected from the database of the Korean Meteorological Administration. Twenty-three growing condition variables were developed as explaining variables for alfalfa forage biomass production. Among them, twelve variables were chosen based on the significance of the partial-correlation coefficients or potential agricultural values. The selected partial correlation coefficients between the variables and alfalfa forage biomass ranged from -0.021 to 0.696. The influence of the selected twelve variables on yearly alfalfa production was summarized into three dominant factors through factor analysis. Along with the accumulated temperature variables, the loading scores of the daily mean temperature higher than 25℃ were over 0.88 in factor 1. The sunshine duration at temperature between 0℃-25℃ was 0.939 in factor 2. Precipitation days were 0.82, which was the greatest in factor 3. Stepwise regression applied with the three dominant factors resulted in the coefficients of factors 1, 2, and 3 for 0.633, 0.485, and 0.115, respectively, and the R-square of the model was 0.602. The environmental conditions limiting alfalfa growth, such as daily temperature higher than 25℃ or daily mean temperature affected annual alfalfa production most substantially among the growing condition variables. Therefore, future cultivar selection should consider the capability of alfalfa to be tolerant to extreme summer weather along with biomass production potential.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.47-53
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• 2023

With the advent of the 4th Industrial Revolution, diverse and a large amount of data has been accumulated now. The agricultural community has also collected environmental data that affects the growth of crops in smart farms or open fields with sensors. Environmental data has different features depending on where and when they are measured. Studies have been conducted using collected agricultural data to predict growth and yield with statistics and artificial intelligence. The results of these studies vary greatly depending on the data on which they are based. So, studies to enhance data quality have also been continuously conducted for performance improvement. A lot of data is required for high performance, but if there are outlier or missing values in the data, it can greatly affect the results even if the amount is sufficient. So, adjustment of outlier and missing values is essential in the data preprocessing. Therefore, this paper integrates data collected from actual farms and proposes a adjustment system for outlier and missing values based on it.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.347-352
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• 1996

These experiments were conducted to monitor the change in $NO_3{^-}-N$ in a plastic film house where $NO_3{^-}-N$ have been accumulated in the soil of high level (about 370 mg/kg) The objective of this study was to obtain the information needed to establish the N Fertilizer recommendation based on the available N content in the soil for vegetable cultivation. The cultivated crops were chinese cabbage in the spring, lettuce in the summer, and chinese cabbage in the autumn. The crops were cultivated with and without N application. The concentration of $NO_3{^-}-N$ in the soil was analysed before and after the cultivation of each crop. When $NO_3{^-}-N$ in the soil is as high as 370 mg/kg. even without N application, the yield of the first season crop, cabbage in the spring was 175 ton/ha and that of second season crop, lettuce in the summer was 53 ton/ha. These yields were comparable with those obtained under the application of N fertilizer: meaning that no N application would be needed for those crops when $NO_3{^-}-N$ in the soil is as high as 370 mg/kg. The yield of third crop, cabbage in the autumn was higher under N application than that under no N application by 62%. The fate of $NO_3{^-}-N$ in the soil differed along with the crop sequence. In the first crop, 14.5% was absorbed by crop, 25.4% remained in the soil and 60.1% was unaccounted for. In the second season, 25.3% was absorbed by crop, 51.8% remained in the soil and 22.9% was unaccounted for. In the third crop, 62.8% was absorbed by crop, 19.4% remained in the soil and 16.8% was unaccounted for.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.179-185
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• 2013

This study was carried out to find a reasonable irrigation method of a nutrient solution for the phenolic foam slab (foam LC) used in a trial experiment to substitute the rockwool slab in the production of paprika (Capsicum annuum 'Veyron'). 100, 90, and 80 mL of a nutrient solution was supplied per plant each time when the accumulated radiation reached to 100, $90J{\cdot}cm^{-2}$, and they were named as the 100-100, 90-90, and 90-80 treatment, respectively. The drain percentage per plant of the 100-100 treatment was high by 33.8% in rockwool and 36.7% in foam LC (Lettuce Cube) and that of 90-80 treatment was low by 30.4% and 33.7%. The water content and EC of the rockwool slab were maintained in the range of 63.6-68.9% and $4.4-5.1mS{\cdot}cm^{-1}$, while those of the foam LC slab were in the range of 52.9-58.8% and $5.5-6.5mS{\cdot}cm^{-1}$. The plant height and leaf size of the 100-100 and 90-90 treatments increased in a similar manner, while those of the 90-80 treatment decreased and those of the rockwool were greater than those of the foam LC. The fruit size and weight of the 100-100 and 90-90 treatments were similarly bigger and heavier than those of the 90-80 treatment. The number of fruits harvested per plant was the greatest in the 90-80 treatment with 8 and 8.3 fruits in the rockwool and foam LC. The number of marketable fruits in the rockwool and foam LC was the greatest with 18.1 and 18.2, respectively, in the 90-90 treatment, while that in the 90-80 treatment was 17.2 and 16.8, respectively. The number of unmarketable fruits of the 90-80 treatment was the greatest (1.7-1.8 fruits per plant) in both the rockwool and foam LC, and most of them were small sized or blossom end rot fruits. The yield of the 90-90 treatment was the greatest among the irrigation.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.357-371
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• 2017

In this study we evaluated the availability of hairy vetch in citrus (Citrus unshiu Marc.) orchards of volcanic ash soils. The responses to increasing seeding rates and various growing conditions such as altitude, accumulated temperature, and soil chemical properties etc, were analyzed by means of the seedling establishment rate, weed occurrence ratio, and shoot biomass yield of hairy vetch. Field experiments were conducted at five citrus orchards by altitude from Sep. 2015 to Apr. 2016 in Jeju Island, Republic of Korea. Hairy vetch used in the study was 'Cheongpyungbora', developed by National Institute of Crop Science. Seeding rates of hairy vetch consisted of 30, 60 and $90kg{\cdot}ha^{-1}$. Results showed that the seedling establishment rates of hairy vetch were quite similar regardless of seeding rates in all fields and weed occurrence ratio at 30, 60 and $90kg{\cdot}ha^{-1}$ of seeding rates were 11.8, 3.8, and 5.1% (dry wt.), respectively. Both 60 and $90kg{\cdot}ha^{-1}$ of seeding rates, the weed occurrences were decreased by 96.2% and 94.9%. The nitrogen production of hairy vetch at 30, 60 and $90kg{\cdot}ha^{-1}$ of seeding rates were 254, 316, and $315kg{\cdot}ha^{-1}$, respectively. Both 60 and $90kg{\cdot}ha^{-1}$ of seeding rates, The nitrogen production were increased by 24%, compared to $30kg{\cdot}ha^{-1}$ of seeding rate. In these results we were considered that the cost-efficient seeding rate of vetch was $60kg{\cdot}ha^{-1}$ in citrus orchards. Also, this study showed that the shoot biomass of hairy vetch and various cultivative factors were related and The nitrogen production of hairy vetch had a little bit of positive correlation (R=0.2714) with accumulated temperature and considerable correlations with some items (EC ($R=0.4520^{**}$) and exchangeable K ($R=0.4078^{**}$)) of soil chemical properties. Therefore, we were considered that hairy vetch can be used as a leguminous cover crop in citrus orchards, the calculation formula (Y=4.4097X + 33.594 (R=0.9547)) can be suggested for nitrogen yield of hairy vetch by using the shoot fresh weight (X).