• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.4
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• pp.293-303
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• 2017

To elucidate the physiological responses of rice plants to the essential mineral silicon (Si), we assessed the effects of treatments with Si, nitrogen ($NH_4NO_3$; ammonium nitrate), and calcium ($CaCl_2$; calcium chloride), independently or in combination on mineral uptake rates and levels of the hormones abscisic acid (ABA), gibberellin ($GA_1$) and jasmonic acid (JA). We found that nitrogen and calcium uptake was inhibited by Si application. However, solo application of nitrogen or calcium did not affect Si uptake. Compared to the untreated plants, the application of Si, $NH_4NO_3$ or $CaCl_2$ increased the endogenous hormone levels in treated plants. In particular, the concentrations of $GA_1$ and JA increased significantly after the application of Si or $NH_4NO_3$. The level of $GA_1$ observed after a treatment (solo or combine) with Si, and $NH_4NO_3$ was higher than that of the control. By contrast, independent application of $CaCl_2$ or a combined treatment with Si and $CaCl_2$ did not alter $GA_1$ levels. The highest level of $GA_1$ was present in plants given a combination treatment of Si and $NH_4NO_3$. This effect was observed at all time points (6 h, 12 h and 24 h). Endogenous JA contents were higher in all treatments than the control. In particular, a combination treatment with Si and $NH_4NO_3$ significantly increased the JA levels in plants compared to other treatments at all time points. A small increase in JA levels was observed after 6 h in plants given the $CaCl_2$ treatment. However, JA levels did not differ between plants given a $CaCl_2$ treatment and controls after 12 h or 24 h of exposure. We conclude that treatment with $CaCl_2$ alone does not affect endogenous JA levels in the short term. Endogenous ABA contents did not show any differences among the various treatments.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.313-319
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• 2006

Two hundred bacterial strains were isolated from the soil around healthy tomato plants in a polyvinyl house, where most of the other plants showed bacterial wilt symptoms. The strains were screened in vitro for their antibacterial activity. Among them, a strain, KPB3 showed strong bactericidal activity against bacterial wilt pathogen, Ralstonia solanacearum. The strain KPB3 was identified using physiological and biochemical tests, and 16S rRNA analyses. Based on these tests, the strain was found to be closer to genus Paenibacillus. To control the bacterial wilt caused by R. solanacearum, greenhouse experiments were conducted to determine the effectiveness of the Paenibacillus strain KPB3. Drench application of this strain ($4{\times}10^8$ CFU $mL^{-1}$) into the pots containing tomato plants, post-inoculated with the pathogen, R. solanacearum could drastically reduce the disease severity, compared to the non-treated plants. To evaluate effectiveness of this strain under field conditions, experiments were carried out in polyvinyl houses infested with R. solanacearum, during spring and autumn of the year 2006. It was observed that, during spring, bacterial wilt was more prevalent compared to the autumn. During spring, 50.9% disease incidences occurred in non-treated controls, while, Paenibacillus strain KPB3 treated plants showed 24.6% disease incidences. Similarly, during autumn, around 17.2% plants were infected with bacterial wilt in non- treated polyvinyl houses, compared to the Paenibacillus strain KPB3 treated plants, which showed 7.0% disease incidences. These results demonstrated that, Paenibacillus strain KPB3 is a potential biological control agent against bacterial wilt caused by R. solanacearum, effective under greenhouse as well as field conditions. This is the first report showing biocontrol of R. solanacearum using a Paenibacillus spp. under field conditions.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.71-89
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• 1988

This study was conducted to evaluate the effect of a growth retardant, Paclobutrazol on the growth, yield and its components. and physiological traits in peanut cv. Saeddle (early variety) and Nampung (medium variety). The results are summarized as follows : Main stem and branch length of both varieties were remarkably retarded at early growth stage application, but the retardation effect was reduced at late growth stage application. Number of branches was increased remarkably by treating 60ppm at 20days after seedling (DAS) in early variety. Lodging ill medium variety was not observed through growth period when 120ppm of Paclobutrazol was applied while lodging was not appeared between 40 DAS and 80 DAS in early variety. The numbers of riped pods in early variety was increased when application of 120ppm at 40 DAS was made while it was increased as application of 120ppm at 90 DAS in the medium variety. Cercospora leaf spot was reduced by spraying at 40 or 50 DAS regardless of concentration and varieties. Chlorophyll content and photosynthetic activity increased when paclobutrazol was applied during 40-60 DAS in early variety while these were observed at 90 DAS in medium variety. Seed weight tended to increase as paclobutrazol application was delayed. The ratio of pods to seeds was higher at 60ppm-40 DAS in early variety while it was higher at 120ppm-90 DAS in medium variety.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.508-514
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• 2016

Effects of the ethyl acetate fraction from gomchwi (Ligularia fischeri) extract against high $glucose/H_2O_2-induced$ oxidative stress and in vitro neurodegeneration were investigated to confirm the physiological property of the extract. The ethyl acetate fraction of gomchwi extract showed the highest total phenolic contents than the other solvent fractions. An anti-hyperglycemic activity of the ethyl acetate fraction was evaluated using the ${\alpha}-glucosidase$ inhibitory assay, and the half maximal inhibitory concentration ($IC_{50}$) value for ${\alpha}-glucosidase$ was found to be $727.64{\mu}g/mL$. In addition, the ethyl acetate fraction showed excellent 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt radical scavenging activity, and inhibition of malondialdehyde production. The ethyl acetate fraction also decreased intracellular reactive oxygen species, whereas neuronal cell viability against high glucose/$H_2O_2$-induced cytotoxicity was found to be increased. Finally, 3,5-dicaffeoylquinic acid as a main phenolic compound in the ethyl acetate fraction was analyzed by high-performance liquid chromatography. These results suggest that gomchwi might be a good natural source of functional materials to prevent diabetic neurodegeneration.

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.89-99
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• 1987

The changes of lipid components in apple peels which effects physiological characteristic in apple storage, and pigment which is important base in quality, were investigated in terms of temperature and pressure. The results obtained were as follows ; The contents of total lipid of Ralls which is resistant to cold temperature were higher than those of Fuji. The contents of total lipid of Fuji and Ralls were decreased up to about 60 days and then increased up to the final stage of storage. Especially, the increasing rate at low temperature storage was greater than at normal temperature storage. In the case of Fuji, the contents of neutral lipid of normal temperature were increased up to 90 days, while those of low temperature were decreased up to 60 days and then increased up to 90 days. The contents of glycolipid, in both Fuji and Ralls were decreased up to about 30 days and then increased up to about 60 days and the decreased up to 90 days. The contents of phospholipid in Fuji were decreased during storage, while those in Ralls were appeared very slight changes. The ratios of unsaturated fatty acid to saturated fatty acids in neutral lipid of Fuji were decreased during storage, but those of Ralls were increased. Those of glycolipid of Fuji were decreased up to 60 days and then increased up to 90 days, while those in Ralls were increased during storage. In both Fuji and Ralls, those of phospholipid increased during storage and were high in order of sub-atmospheric pressure at $1^{\circ}C$ (SAP-L), normal atmospheric pressure at $1^{\circ}C$ (NAP-L), sub-atmospheric pressure at $20^{\circ}C$ (SAP-N) and normal atmospheric pressure at $20^{\circ}C$(NAP-N) for storage condition. The contents of chlorophyll of Ralls were higher than those of Fuji and the decreasing rate was the lowest in SAP-L. The changes of carotenoid and anthocyanin contents were the greatest increasing at NAP-N and colouring was delayed at SAP-L.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.181-188
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• 1992

To study the effect of alginic acid on modulation of the aging process, Sprague-Dawley(SD) male rats were fed the diets containing 0, 3, 6 and $9\%$ alginic acid isolated from brown algae(Undaria pinnatifida) for 16 weeks. The effects of alginic acid on body weight, malondialdehyde(MDA) content, peroxidizability index, cholesterol and phospholipid levels, cholesterol/phospholipid(Ch/Ph) molar ratio, and fatty acid compositions in liver membranes were investigated. Increasing alginic acid level in diets did not alter food intakes but effectively decreased body weights gain(p<0.01-0.005). Malondialdehyde(MDA) contents of diets containing 6 and $9\%$ alginic acid were effectively decreased in ranges of $54.1-43.0\%$ in mitochondria, and $65.5-87.7\%$ in microsome compared with $100\%$ of control group. Cholesterol levels of all diets containing alginic acid were significantly decreased in ranges of $87.0-72.3\%$ in mitochondria, and $87.4-68.1\%$ in microsome compared with $100\%$ of control group. Phopholipid levels in microsome were significantly decreased by diets containing 3 and $ 6\%$ alginic acid but Ch/Ph molar ratios in both membranes were decreased by diets containing 3 and $6\%$ alginic acid. Increasing alginic acid level in diets significantly decreased total fatty acid but effectively increased linoleic acid in microsome except for diet containing $9\%$ alginic acid. These data on liver membranes suggest that alginic acid added to diets can modulate the physiological changes if the aging process.

• Food Science and Preservation
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• v.19 no.6
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• pp.799-806
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• 2012

This experiment was conducted to establish the optimum conditions for high $CO_2$ gas treatment in combination with a proper gas-permeable packaging film to maintain the quality of fig fruit (Ficus carica L). Among the fig fruits with different high $CO_2$ treatments, the quality change was most effectively controlled during storage in the 70%-$CO_2$-treated fig fruit. Harvested fig fruit was packaged using microperforated oriented polypropylene (MP) film to maintain the optimum gas concentrations in the headspace of packaging for the modified-atmosphere system. MP film had an oxygen transmission rate of about $10,295cm^3/m^2$/day/atm at $25^{\circ}C$. The weight loss, firmness, soluble-solid content (SSC), acidity (pH), skin color (Hunter L, a, b), and decay ratio of the fig fruits were monitored during storage at 5 and $25^{\circ}C$. The results of this study showed that the OPP film, OPP film + 70% $CO_2$, and MP film+70% $CO_2$ were highly effective in reducing the loss rate, firmness and decay occurrence rate of fig fruits that were packaged with them during storage. In the case of using treatments with packages of OPP film and OPP film+70% $CO_2$, however, adverse effects like package bursting or physiological injury of the fig may occur due to the gas pressure or long exposure to $CO_2$. Therefore, the results indicated that MP film containing 70% $CO_2$ can be used as an effective treatment to extend the freshness of fig fruits for storage at a proper low temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.185-192
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• 1987

A green house experiment was conducted to find out the acetylene reducing and $N_2$-fixing activity from photosynthetic and aerobic heterotrophic nitrogen fixing microorganisms in submerged paddy soil under different agricultural locality, soil series, soil texture, soil type, and drainage condition in which samples taken from without nitrogen treatment plot of NPK trials on 16 sites of the farmer's field. The results obtained were summarized as follows: 1. The highest acetylene reducing activity was observed at 7 days after incubation in the light condition (photo synthetic microbes+heterotrophic bacteria) while it was observed at 35 days incubation in the dark condition (heterotrophic bacteria). 2. Among the soil series, photosynthetic nitrogen fixing activity was pronounced more in Jangae, Ogcheon and Hwadong series while lower was obtained in Buyong and Daejeong series. Aerobic heterotrophic nitrogen fixing activity was high in Buyong and Daejong series. 3. Estimated amount of $N_2$-fixation from acetylene reducing activity was equivalented to 3.0 mg in light condition and 4.9 mg/100g/105 days in dark condition. 4. Among the agricultural locality, photosynthetic nitrogen fixing activity was high in rather warm southern part while heterotrophic nitrogen fixing activity was predominated more in mountainous area and Chungcheong continental. 5. Photosynthetic nitrogen fixing activity was predominated in high productive soil while aerobic heterotrophic nitrogen fixing activity was pronounced more in crose coarse sandy soil. 6. The soils properties of high photosynthetic nitrogen fixing activity were constituted of poorly or imperfectly drained clay or clay loam soil while heterotrophic nitrogen fixing activity was pronounced more in well to moderately well drained sandy or sandy loam soil.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.423-433
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• 2021

This study was performed to examine the neuroprotective effect of the ethyl acetate fraction from Eucommia ulmoides oliver leaf (EFEL) on PM_2.5-induced cytotoxicity. EFEL had higher total phenolic and flavonoid contents than the other fractions. In ABTS and DPPH radical scavenging activities, the IC₅₀ of EFEL was measured as 212.80 and 359.13 ㎍/mL, respectively. To investigate the neuroprotective effect of EFEL, MTT and DCF-DA assays were performed on HT22, MC-IXC, and BV-2 cells. EFEL effectively decreased PM_2.5-induced intercellular reactive oxygen species (ROS) content and inhibited PM_2.5-induced cell death. In the results of protein expression related to cellular cytotoxicity on microglial cells (BV-2), EFEL had an improvement effect on cell apoptosis and inflammatory pathways. Rutin and chlorogenic acid were identified as the main physiological compounds. Moreover, it was expected that EFEL, including rutin and chlorogenic acid, could be functional food substances with neuroprotective effects against PM_2.5-induced oxidative stress.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.224-230
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• 2018

This study was conducted to investigate the effects of concentrate feeding frequency on weight change and the colic of Jeju cross-bred horses. Around thirty-six old Jeju cross-bred horses were divided into three groups and were investigated by feeding the concentrate feed at 2.5% of their body weight 2 times, 3 times, or 4 times daily. Although the total weight gain and daily weight gain for the different feeding frequencies were higher with feeding concentrates 4 times daily compared with the other treatment groups, there was no statistically significant difference between the groups (p>0.05). Rectal temperatures were above the normal range in weeks 11 to 12, but there was no statistically significant difference between the groups (p>0.05). Fecal pH was below the normal range in weeks 1 to 12, but there were no colic symptoms with any of the treatments and there was no statistically significant difference between the groups (p>0.05). When feeding concentrate feed at 2.5% of body weight, it was assumed that trying to feed it several times per day would help to prevent colic; however, there was no difference in weight gain, blood characteristics, and physiological characteristics in accordance with the number of feeding times.