• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.323-323
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• 2017

In many sub-Saharan African countries, boosting rice production is a pressing food security issue. To contribute to the increase in rice production, we have developed lines of NERICA 1 introgressed with the gene for spikelet number, Gn1a, and the gene for primary rachis-branch number, WFP by cross breeding. The performance of rice lines introgressed with the genes for yield related traits can be affected by cultivation environment and management. Thus, in this study, we aimed to evaluate the lines of NERICA 1 introgressed with Gn1a or/and WFP for yield and yield components under different nitrogen fertilization conditions in Kenya. A field trial was conducted at a paddy field in Kenya Agricultural and Livestock Research Organization-Mwea, Kirinyaga County ($0^{\circ}39^{\prime}S$, $0^{\circ}20^{\prime}E$) from August 2016 to January 2017. Eight lines of NERICA 1 introgressed with Gn1a and/or WFP, and their parents, NERICA 1 and ST12, were grown under 0 (NF) and $75(SF)kg\;N\;ha^{-1}$. At maturity, five hills per plot were harvested to determine the yield and yield components. The number of primary and secondary rachis-branches per panicle was measured on the longest panicle in each hill. Under SF, the introgression of WFP to NERICA 1 increased the number of primary and secondary rachis-branches by 27 and 25%, respectively. On the other hand, Gn1a did not increase the number of primary rachis-branches, whereas the number of secondary rachis-branches was increased by 38% on average. The number of primary and secondary rachis-branches of the lines introgressed with both genes increased by 25 and 56%, respectively. Although grain number per panicle increased 33% by Gn1a, 34% by WFP, and 43% by Gn1a+WFP, the yield increase by Gn1a, WFP, and Gn1a+WFP was only 14, 7, and 14%, respectively. The suppression of the yield increase was mainly attributed to the decline in the filled grain ratio. Under NF, WFP increased the number of primary and secondary rachis-branches by 20 and 19%, respectively. The introgression of both genes increased the former and the later by 19 and 35%, respectively. However, Gn1a did not change them under NF. Thus, even under NF, grain yield increased 11% by WFP and 24% by Gn1a+WFP due to the increased grain number although filled grain ratio declined. Our findings suggest that the introgression of Gn1a and WFP could contribute to the rice productivity improvement in sub-Saharan Africa even under low fertility conditions. Improving filled grain ratio of the lines introgressed with these genes by further breeding and fertilization management will be the focus of subsequent work.

• Korean Journal of Environmental Agriculture
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• v.33 no.2
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• pp.103-110
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• 2014

BACKGROUND: Azadirachta indica has been widely used as environment-friendly organic materials because of its insecticidal properties. This study was carried out to investigate the acute toxicity and the subacute toxicity of Azadirachta indica extract(AIE) in rats. METHODS AND RESULTS: For the oral acute toxicity test, Sprague-Dawley rats were gavaged with 2.0 g/Kg bw of AIE. The $LD_{50}$ value was greater than 2.0 g/Kg bw for both male and female rats. For the subacute toxicity study, rats were treated with AIE at doses of 0.5, 1.0, 2.0 mg/Kg bw once a day for 4 weeks(n=10 animals per each group). There were no significant changes in body weight, food intake and water consumption observed during the experimental duration. In addition, no difference of relative kidney weight was observed among all treated groups. Serum creatinine level in the AIE 2.0 g/Kg group increased significantly compared with that of control group in male rats, but serum blood urea nitrogen was significantly decreased in a dose-dependent manner (p<0.05). Significant increase of serum cholesterol levels were observed in all AIE groups, compared with the control group, in the female rats (p<0.05). However, histopathological examination of the kidney did not reveal any significant lesions in all groups. CONCLUSION: On the basis of results, it could be concluded that oral administration AIE didn't cause any toxic response in kidney, except the increased serum cholesterol.

• Journal of Nutrition and Health
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• v.47 no.6
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• pp.452-462
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• 2014

Purpose: The purpose of the study was to evaluate the status of events and importance-performance analysis (IPA) between industry and school foodservices. Methods: The study subjects were dietitians in industry foodservices (n = 73) and nutrition teachers in school foodservices (n = 135) in the Jeonbuk area. Demographic characteristics, status of events, and problems of implementing events were assessed using a self-administered questionnaire. Results: Approximately 67% of industry foodservices had implemented an event a month, whereas 40.7% of school foodservices did not implement events for students. The type of events that industry and school foodservices had implemented most frequently were Sambok event, Dongji event, Daeboreum event, Spring-Namul event, and Chuseok event. The industry foodservices had significantly higher average scores for performance of events than those of the school foodservices (p < 0.001). In the Importance-Performance Analysis (IPA), high importance and high performance (A area: doing great) in industry foodservices were seasonal events, traditional festival day events, anniversary events, traditional seasonal events, and personal memory events, whereas in school foodservices were traditional festival day events, traditional seasonal events, school events, and environment events. Conclusion: These results showed that events are important for the increase in customer satisfaction. Therefore, it is necessary to consider educational programs on event implementation for dietitians and employees in industry and school foodservices.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.1-15
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• 2020

This study was conducted to determine whether invasive muskrats settle in the natural ecosystem of Korea. The study also aimed to provide information on the selection of target areas, basic behavioral characteristics, and habitat use-related data, all of which are essential for effective management strategy establishment and site management. To this end, a trend in international muskrat management was identified to examine the management direction according to the settlement stage. We also secured the location of 72 domestic farmers and classified five regions in Gyeonggi-do, Chungcheongnam-do, Gyeongsangbuk-do, and Sejong Special Self-governing City into regions with high potential for natural leakage to raise the need for a quick survey. We determined that muskrats successfully settled in the natural ecosystem of Korea, based on the fact that we consistently identified a muskrat habitat at the same point for three years, from 2016 to 2018, the age of the captured population was estimated to be 1.2 years, and there had been no additional make-up factors near the habitat since 2012. The muskrats that settled in Korea showed a small home range of 0.0027 ㎢ (MCP 95%) and were estimated to show regular mobility before Spring and Autumn. Also, the areas where the muskrat habitat was observed had a high level of habitat environment disturbance and their ecological and food intake characteristics reflected that disturbance. Muskrat traces were high in hydrophyte vegetation, which can be used as a hideout in open waters and where the growth of both floating leaved plants and floating plants are prevalent. Since international invasive muskrats have already settled in the domestic ecosystem and there is concern about their proliferation in the future, the government must consider a preemptive response and scientific management.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.1
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• pp.59-69
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• 2000

Environmental factors and phytoplankton community have been bimonthly investigated in order to clarify the bioecological characteristics of coral habitats around Moonsom at the southern Cheju Island from September 1995 to July 1996. Annual mean temperature and annual mean salinity were $17.4^{\circ}C$ and 34.06 psu, respectively, showing lower temperature-higher salinity in winter and higher temperature-lower salinity in summer, which means such conditions are inadequate for coral reef formation. Nutrient concentrations represent that total nitrogen ranged from $0.07{\sim}10.08\;{\mu}M$, phosphate from $0.05{\sim}1.70\;{\mu}M$, and silicate from $3.08{\sim}21.86\;{\mu}M$. The N/P ratio showed the range of 9.59-10.60 with decreasing offshore-ward, which means the phytoplankton community could be limited by nitrogen sources. Annual mean euphotic depth was 32.0m (18.9m-48.6m) with difference according to season and reveals the close relationship with the depth of coral distribution. Chlorophyll a concentrations of phytoplankton ranged from $0.12{\sim}1.51\;{\mu}g\;L^{-1}$ and standing crops from $1.5{\times}10^3{\sim}7.0{\times}10^5\;cells\;L^{-1}$, showing higher at inshore than at offshore with a blooming in May. A total of 128 species of phytoplankton occurred in all stations, representing 99 spp. of diatoms, 26 spp. of dinoflagellates, 2 spp. of silicoflagellates and 1 sp. of blue-green algae. Diatoms are main taxa in all seasons except for occupying by dinoflagellates in summer. Among dominant species, fParalia sulcata (Ehrenberg) Cleve and Cylindrotheca closterium (Ehrenberg) Lewin & Reimann were predominant and are likely to be main food sources for coral community. Annual mean species diversity index (H') was 1.84, showing lower than around the coast line of Cheju Island.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.289-296
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• 2001

The main objective of this topic is to establish strategies and to plan biotechnology researches which are related to the agricultural improvements especially focusing on the crop breeding in Korea. From 1960's to 1980's government policy had been emphasized to develope high yielding cultivars for the self sufficient supply of the staple food crops. As a result, considerable increase of rice production has been made with accumulating technology and man's powers. Recently genetically modified crops harboring useful characteristics have been developed using biotechnology and released in the developed countries. National research institutes and private companies have been developed biotechnology researches to establish competitive capabilities, however they have not been successfully used in commercialization. Therefore it is necessary to promote the practical. application by connecting molecular technology with conventional breeding. Proposed research projects are; (1) basic researches including plant genome studies, (2) developing new cultivars through gene transformation, (3) screening and producing antioxidants, secondary metabolite substances and edible vaccines. To set a government policy, both domestic and international research trends were reviewed and possibility of success based on the economic view point were discussed. The intellectual property and preservation of environment play a key role to decide the research priority. It is also necessary for us to make one step system for the distribution of research resources such as microorganisms, genes cloned, plant seeds and research informations for promoting research activities.

• Applied Biological Chemistry
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• v.37 no.3
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• pp.143-147
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• 1994

Four samples of commercially manufactured yogurts (plain, drinking type) were purchased and evaluated their physico-chemical properties, buffering capacity. And the survival rate of lactic acid bacteria and their ${\beta}-galactosidase$ activity under the acidic conditions (in vitro) were investigated. The values of pH, titratable acidity, viscosity and viable cell counts of yogurts were $3.71{\sim}4.08$, $0.990{\sim}1.045%$, $256{\sim}3164\;cps.$ and $10^8{\sim}10^9\;cfu/ml$, respectively. The volume of 1.0 M-HCl required to reduce the pH of yogurt (50 ml) to minus 2 value was $3.58{\sim}4.33\;ml$. When commercial yogurts were incubated at $37^{\circ}C$ for 120 minutes under the acidic conditions (pH 3.5, 2.5, 1.5), the survival rates of lactic acid bacteria in yogurt were $3.5{\times}10^{-2}{\sim}3.6{\times}10^{-1}%$ at pH 2.5, $8.3{\times}10^{-5}{\sim}4.2{\times}10^{-3}%$ at pH 1.5, respectively, but there was no significant difference at pH 3.5. The remaining activities of ${\beta}-galactosidase$ were $9.4{\sim}36.2%$ at pH 2.5, $4.2{\sim}19.0%$ at pH 1.5, respectively. These results suggested that a significant number of lactic acid bacteria in yogurt might be destroyed in the hostile environment of the stomach, but ${\beta}-galactosidase$ activity from yogurt might be somewhat maintained probably due to the protecting effect by its cell wall and membrane.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.50-60
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• 2008

We performed the experiment to evaluate the effect of different DO concentrations (0.5, 4.5 and 9.0 $mgO_2L^{-1}$) and water depths (20, 50 and 80 cm) on the filtering rate, mortality, and pseudifeces production of Unio douglasiae against the cyanobacterial bloom (mainly Microcystis aeruginosa). A solitary-living bivalve U. douglasiae was collected in the upstream region of the North Han River (Korea). The harvested mussels were carefully transferred to the laboratory artificial management system, which was controlled temperature $(18{\pm}2^{\circ}C)$, flow rate (10L $h^{-1}$), food $(Chlorella^{TM})$, sediment (pebble and clay), light intensity (ca. $20{\mu}mol$ photons), and photocycle (12 L : 12 D). In the field observation, the mussel mortality was significantly correlated with water temperature, pH and DO concentration (P<0.05). The mortality was decreased with water depth; 65, 90, 80% of mortality at 20, 50, 80 cm water-depth, respectively. Filtering rate (FR) showed the highest value at 50 cm water depth, and thereby the concentration of chlorophyll-${\alpha}$ decreased continuously by 94% of the control at the end of the experiment. In contrast, FR decreased by 34% of the initial concentration at 20 cm water depth. Over the given water-depth range, the mussel FR ranged from $0.15{\sim}0.20L\;gAFDW^{-1}hr^{-1}$ during the 18hrs of experiment, and thereafter, they appeared to be approximately 0.11, 0.26 and 0.30 L $gAFDW^{-1}hr^{-1}$ at 20, 50 and 80cm water depth, respectively. FR was highest with the value of 0.46L $gAFDW^{-1}hr^{-1}\;at\;0.5mgO_2 L^{-1}$ at the early stage of the experiment, while it increased with DO concentration. Maximum pseudofaeces production was 11.2 mg $gAFDW^{-1}hr^{-1}\;at\;9.0mgO_2L^{-1}$. Our results conclude that U. douglasiae has a potential to enhance water quality in eutrophic lake by removing dominant cyanobacteria, but their effects vary with environmental parameters and the water depth at which they are located.

• Economic and Environmental Geology
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• v.50 no.5
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• pp.341-352
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• 2017

Along with Cs-137 (half-life: 30.17 years), Sr-90 (half-life: 28.8 years) is one of the most important environmental monitoring radioactive elements. Rapid and easy monitoring method for Sr-90 using Laser-Induced Breakdown Spectroscopy (LIBS) has been studied. Strontium belongs to a bivalent alkaline earth metal such as calcium and has similar electron arrangement and size. Due to these similar chemical properties, it can easily enter into the human body through the food chain via water, soil, and crops when leaked into the environment. In addition, it is immersed into the bone at the case of human influx and causes the toxicity for a long time (biological half-life: about 50 years). It is a very reductive and related with the specific reaction that makes wet analysis difficult. In particular, radioactive strontium should be monitored by nuclear power plants but it is very difficult to be analysed from high-cost problems as well as low accuracy of analysis due to complicated analysis procedures, expensive analysis equipment, and a pretreatment process of using massive chemicals. Therefore, we introduce the Laser-Induced Breakdown Spectroscopy (LIBS) analysis method that analyzes the elements in the sample using the inherent spectrum by generating plasma on the sample using pulse energy, and it can be analyzed in a few seconds without preprocessing. A variety of analytical plates for samples were developed to improve the analytical sensitivity by optimizing the laser, wavelength, and time resolution. This can be effectively applied to real-time monitoring of radioactive wastewater discharged from a nuclear power plant, and furthermore, it can be applied as an emergency monitoring means such as possible future accidents at a nuclear power plants.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.254-259
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• 2012

Peeling damage of trees is usually caused by Cervidae such as deer, roe deer because of the lack of food in forests. However, it happens as part of the developing of antlers in Jeju Island when the roe deer try to remove the Velvet-the skin of the antlers. The research area is the Hannam experimental forest (400 m up to 500 m above sea level) of Korea Forest Research Institute in Jeju Island, and the survey was carried out along the 6 km long of forest road with 5 m width on both sides. Twenty five tree species (total 267 stands) are damaged by peeling; 18 (134 stands) deciduous broad-leaved species, 5 (71 stands) in evergreen broad-leaved species, 2 (62 stands) coniferous species. The most common damaged species are in order of Daphniphyllum macropodum, Cryptomeria japonica, Lindera erythrocarpa, Clerodendrum trichotomum, Zanthoxylum schinifolium. Mainly damaged trees are approximately 3~4 years old saplings, and they show the mean height $120.7{\pm}42.4cm$, diameter measured at 5 cm height $1.5{\pm}0.5cm$. The Lowest peeling beginning height is $22.1{\pm}10.1cm$, and the mean length of peeling is $27.5{\pm}10.6cm$. Once the peeling damage happens, the saplings are infected by fungi secondly, and are distorted or dead, therefore the future structure of warm-temperate forests could be in influenced in species. Warm-temperate forest landscape and species change related to the climate change is a rising issue in Jeju Island. However the changes caused by peeling damage also could be an important issue in the natural process of forest environment, afforestation, local nursery and sustainable forest management of Jeju Island.