• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.201-207
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• 2022

Fescues, which are widely cultivated as grasses and forages around the world, are often naturally infected with the endophyte, Epichloë. This fungus, transmitted through seeds, imparts resistance to drying and herbivorous insects in its host without causing any external damage, thereby contributing to the adaptation of the host to the environment and maintaining a symbiosis. However, some endophytes, such as E. coenophialum synthesize ergovaline or lolitrem B, which accumulate in the plant and impart anti-mammalian properties. For example, when livestock consume excessive amounts of grass containing toxic endophytes, problems associated with neuromuscular abnormalities, such as convulsions, paralysis, high fever, decreased milk production, reproductive disorders, and even death, can occur. Therefore, pre-inoculation with non-toxic endogenous fungi or management with endophyte-free grass is important in preventing damage to livestock and producing high-quality forage. To date, the diagnosis of endophytes has been mainly performed by observation under a microscope following staining, or by performing an immune blot assay using a monoclonal antibody. Recently, the polymerase chain reaction (PCR)-based molecular diagnostic method is gaining importance in the fields of agriculture, livestock, and healthcare given the method's advantages. These include faster results, with greater accuracy and sensitivity than those obtained using conventional diagnostic methods. For the diagnosis of endophytes, the nested PCR method is the only available option developed; however, it is limited by the fact that the level of toxic alkaloid synthesis cannot be estimated. Therefore, in this study, we aimed to develop a triplex real-time PCR diagnostic method that can determine the presence or absence of endophyte infection using DNA extracted from seeds within 1 h, while simultaneously detecting easD and LtmC genes, which are related to toxic alkaloid synthesis. This new method was then also applied to real field samples.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.33-41
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• 1997

This study was carried out to establish simple and easy methods to judge the survival, senescence and death of the protoplasts in culture system by identifying the marker substance related to metabolic status of the cells. When rice and tobacco protoplasts were cultured in MS and KM-8P media containing 2,4-D or coconut milk ABA decreased especially in the media containing coconut milk, but GA$_3$, IAA and zeatin increased as the cultures progressed. The decrease of ABA and increase of zeatin was especially remarkable. When the supraoptimal amount of osmoticum (mannitol) was added to the culture media ABA decreased after a momentary increase, but other growth hormones slowly increased as the concentration of the osmoticum increased. Contents of individual hormones were contrasted when protoplasts rice and tobacco were cultured on the same medium containing 10mM super mine or NaCl. Tobacco protoplasts were more sensitive to NaCl stress and stopped protoplast division at the late stage of culture. Protoplast viability decreased greatly in 48 hours when the protoplast were at 32$^{\circ}C$ on a medium lacking several components. ABA content increased up to 10 days from incubation in negative proportion to the protoplast viability. On the other hand contents of other growth hormones, especially zeatin, decreased. The present results clearly showed that the contents of individual growth hormones in the plant protoplasts in culture varied sensitively in response to environmental factors that they are faced with. This indicates that the physiological states of the protoplast, such as survival, senescence or death can be simply judged based on the quantitative analysis of those hormones by ELISA.

• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.169-176
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• 2016

Although chemical fertilizers have a quick effect and broad applicability to agricultural fields, they have caused many problems like increasing soil acidity or decreasing soil organic matters. Environmental-friendly agriculture has been attempted in various ways such as organic agriculture, natural farming, low input and sustainable agriculture. The common interest of all environmental-friendly systems is to decrease burden to agricultural environment by low input of agricultural labor and materials. This study was conducted to estimate overwintering capacity and genetic distance among Chinese Milk Vetch (Astragalus sinicus, CMV) collections based on morphological characteristics and AFLP (Amplified fragment length polymorphism) analysis. Furthermore, the effect of CMV as green manure was observed in mix-cultured paddy fields with rice, sesame and sweet-potato. An another objective of this study was also to compare the pattern of weed occurrence in paddy fields with or without CMV and different rice transplanting times. The CMV collected from Paju district in central region of Korea was successively occurring through self-reseeding without artificial management. However, there was no noticeable difference in growth habit between Paju native CMV and introduced CMV from China which is currently used in farm fields. On the basis of multi-dimensional scaling and tree analyses, there are no significant difference of agricultural growth characteristics among Paju and chinese collections only excepting leaf angle and root length. The flowering time of Gurye collection was fast for 1 week as compared to other collections. AFLP that was commonly used for plant classfication, was applied to exam the genetic variation of CMV collections. Total 579 PCR products and 336 polymorphic fragments were generated using 8 primer pairs.

• Korean Journal of Community Nutrition
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• v.15 no.4
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• pp.513-524
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• 2010

This study was designed to examine nutrition label use, self-efficacy, snacking and eating behaviors of middle school students, and to investigate if these characteristics were different by nutrition label use. A cross-sectional survey was conducted to 348 middle school students in Kyunggi, Korea. About a third of subjects read nutrition labels when they purchased snacks/packaged foods. Most nutrition label users were interested in reading information on calories, fat and trans-fat. Self-efficacy of eating/selecting snacks or general nutrition behavior was moderate (mean score: 44.4 out of 60), with significantly higher score in nutrition label users compared to nonusers (p < 0.001). Nutrition label users felt more confident in 9 items out of 15 items of self-efficacy, such as "taking fruits instead of cookies/candy for snack" (p < 0.001), "choosing milk instead of soft drink" (p < 0.01), "not having snacks after dinner" and "avoiding processed foods for snacks" (p < 0.05). Subjects had snacks 1.3 times a day, and nutrition label nonusers consumed snacks more frequently than the counterparts (p < 0.01). About 55% of nutrition label users and 64.7% of nonusers mainly purchased snacks for themselves (p < 0.05). Commonly purchased snacks by adolescents were ice cream, cookies/chips, breads and ramen. Major considerations in purchasing snacks were taste (46.9%) and price (34.6%). In selecting snacks, the influence of friends and parents was greater than the other sources. Based on eating frequency of snacks, nutrition label users were more likely to consume healthy snacks, such as fruit juices, vegetables, milk, yogurt, and potato/sweet potato than nonusers (p < 0.05). Eating behaviors measured by 15 items scored 33.6 out of 45. Nutrition label users showed better eating behaviors, such as "eating meals slowly", "eating foods cooked with plant oil", and "eating out less frequently" (p < 0.05). Study results showed that majority of adolescents did not read nutrition labels, selected snacks for themselves and had somewhat unhealthy foods for snacks. This study also showed the differences in self-efficacy, snacking and eating behaviors between nutrition label users and nonusers. In nutrition education, it is necessary to stress the importance and skills for reading nutrition labels. It is also needed to help adolescents to select healthy snacks and have desirable eating behaviors, as well as increasing self-efficacy.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.12
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• pp.1601-1607
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• 2010

Two experiments were carried out to investigate i) the effects of four levels of lactic acid bacteria inoculants (LAB; 0, $2{\times}10^5$, $3{\times}10^5$ and $4{\times}10^5$ cfu/g fresh forage) and two physical forms of rice straw (whole and chopped rice straw) on silage fermentation quality and nutritive value of rice straw (RS) silage for lactating Holsteins and ii) the effects of the replacement of corn silage (CS) with different inclusion levels (0, 25 and 50%) of LAB treated RS on lactating performance of Holstein dairy cows. Rice straw packed with stretch film was ensiled for 45 d. The results showed that the higher level of LAB inoculants in the silage quadratically decreased pH, $NH_3$-N and acetic acid concentrations and increased the contents of lactic acid and total organic acids. The CP content and DM losses in the silage declined linearly as the level of LAB addition was increased. Compared with whole-plant rice straw silage (WRS), chopped rice straw silage (CRS) dramatically reduced pH by 0.83. The concentrations of $NH_3$-N were similar in WRS and CRS and both were less than 50 g/kg of total N. Chopping rice straw before ensiling significantly enhanced the lactic acid concentration and total organic acids content whereas the concentration of acetic acid declined. The CP, NDF and ADF content of CRS was 13.4, 5.9 and 10.2% lower than in WRS, respectively. Except for butyric acid concentration, significant interaction effects of inoculation level and physical form of RS were found on all fermentation end-products. Our findings indicated that milk yield and composition were not affected by different level of RS inclusion. However, because of the lower cost of WRS, cows consuming a ration in which WRS was partially substituted for CS had 3.48 Yuan (75% CS+25% WRS) and 4.56 Yuan (50% CS+50% WRS) more economic benefit over those fed a CS-based ration. It was concluded that the chopping process and LAB addition could improve the silage quality, and that substitution of corn silage with RS silage lowered the cost of the dairy cow ration without impairing lactation performance.

• Journal of the Korean Society of Food Culture
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• v.13 no.2
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• pp.107-118
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• 1998

A nutrition education program for teachers and caregivers of the preschool children can be most effective when it is based on a comprehensive needs assessment dealing with sociodemographic factors, dietary habits, and nutrition. The purpose of the present study was to investigate current dietary habits and nutrition knowledge of the teachers and caregivers of the day-care centers. Two hundred forty two teachers and caregivers were administered a questionnaire which was designed to ascertain informations on sociodemographic data, dietary habits and nutrition knowledge. Dietary habits of the teachers were found to be significantly different by sociodemographic variables; breakfast skipping/meal irregularities (age, p=0.011); frequency of snacking (education level p=0.031); preference for salty taste(age, p = 0.000, marital status p=0.038); preference for sweet tarte (age p=0.009); preference for vegetables (income level p=0.050); frequency of eating out (age p=0.028, marital status p=0.001); frequency of coffee drinking (age p=0.019). Daycare center teachers' nutrition knowledge level was found to be less than adequate expecially on nutrients that are liable to be deficient in young growing children and their food sources. Proportions of the teachers who answered correctly to the questions on foods rich in vitamin A, iron content of milk, bioavailability of calcium in plant foods were as low as 20.2%-54.5%. The most frequently used sources of nutrition information were mass media such as TV, radio, newspaper and magazines. Only 2.9% of the subjects reported that they obtain nutrition information from health professionals such as nutritionists/dietitians, physicians, and nurses. These findings are applicable at the planning and implementation stages of various nutrition programs for the improvement of dietary habits and nutrition knowledge of the teachers and caregivers of the daycare centers. Further studies are needed to investigate the effects of teachers' dietary of habits and nutrition knowledge on food habits of young growing children.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.689-696
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• 2015

The green manure crops are returned to soil when the plants are still green. The green manure crops play a role in reducing chemical fertilizers, improvement of soil fertility, reduction of soil erosion, weed control, and landscapes effect. Typical green manure crops are barley green manure, hairy vetch, chines milk vetch and clovers. We sowed 49 species of green manure crops in upland soil to increase the usage of green manure crops. We searched the effectiveness of green manure yield, C/N ratio, soil mulching, and landscape effect. The green manure crops that have $5tonha^{-1}$ or more of green manure yield (fresh weight) were 6 gramineous crops, 4 leguminous crops, and 3 others. Green manures yield in a short growth period was higher in gramineous crops than leguminous crops. Among the green manure crops, 3 gramineous crops, 12 leguminous crops, and 3 others were under 25 in C/N ratio. Seven gramineous crops, 8 leguminous crops, and 5 others were over 50% of soil covering rate. Green manure crops that have beautiful flowers were in total 16 kinds, such as 4 gramineous crops, 6 leguminous crops, and 6 others. In result, based on green manure yield and C/N ratio, excellent species in the green manure crops were 4 species (triticale, 2 kinds of hairy vetch, and lupin). Green manure crops that were effective at soil mulching were 20 species, like hairy vetch, oats, sorghum, phacelia, buckwheat, etc. Buckwheat, crotalaria, mustard plant, phacelia, and etc. could be available for landscape crops.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.224-232
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• 2019

Objective: Apart from various climatic differences, corn harvest stage and varieties are two major factors that can influence the yield and quality of corn silage in the tropics. A study was conducted to determine the optimum harvest stage of four corn varieties for silage production in Malaysia. Methods: Corn was harvested at four growth stages; silking, milk, dough, and dent stages from four varieties; Sweet Corn hybrid 926, Suwan, breeding test line (BTL) 1 and BTL 2. Using a split plot design, the treatments were then analysed based on the plant growth performance, yield, nutritive and feeding values followed by a financial feasibility study for potential commercialization. Results: Significant differences and interactions were detected across the parameters suggesting varying responses among the varieties towards the harvest stages. Sweet Corn was best harvested early in the dough stage due to high dry matter (DM) yield, digestible nutrient, and energy content with low fibre portion. Suwan was recommended to be harvested at the dent stage when it gave the highest DM yield with optimum digestible nutrient and energy content with low acid detergent fibre. BTL 1 and BTL 2 varieties can either be harvested at dough or dent stages as the crude protein, crude fibre, DM yield, DM content, digestible nutrient and energy were not significantly different at either stage. Further financial analysis showed that only Sweet Corn production was not financially feasible while Suwan had the best financial appraisal values among the grain varieties. Conclusion: In conclusion, only the grain varieties tested had the potential for silage making according to their optimum harvest stage but Suwan is highly recommended for commercialization as it was the most profitable.

• The Korean Journal of Food And Nutrition
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• v.28 no.4
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• pp.728-736
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• 2015

Cronobacter species (Cronobacter spp.), previously known as Enterobacter sakazakii, are gram negative food borne pathogenic bacteria. They pose a very high risk of infection to neonates and immuno-compromised individuals and can affect the human central nervous system. Consequently, survivors often suffer from severe neurological impairment including hydrocephalus, quadriplegia, and developmental delays. Cronobacter spp. were not only isolated from plant food and products such as cereals, fruits, vegetables, legume products, herbs, and spices but also from animal source foods such as milk, meat, fish, and products made from these foods. Therefore, rapid detection of Cronobacter spp. is essential for food safety. Many detection methods have been developed since the Cronobacter spp. were first reported. However, the development of more rapid, sensitive, and easy-to-use detection methods for the Cronobacter spp. is required. In this review, our aim was to study and compare the available detection methods for Cronobacter spp., including culture-based, molecular biology-based, and immunology-based methods. This study will contribute to the development of new and rapid detection method for Cronobacter spp.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.327-331
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• 2006

This study was carried out to determine the economic injury level of the rice leaffolder,Cnaphalocrocis medinalis G.. The damage aspects of rice plant (at tilling stage) by leaf folders at different larval density per plant were studied in pot experiment (24 cm in diameter, 18 cm in height). One leaf folder consumed 6-7 leaves during larval stage. The damage by leaf folders was simulated by cutting off 0, 10, 30, 50, 70, and 90% of leaves before and after heading stage July 15th (at panicle initiation stage) and August 15th (at milk stage), respectively. When leaves were cut before the heading of rice, the linear relationships between the leaf cutting rate (X) and each factors of yield (Y) were as following; for grain maturity it was Y = -9.379X + 83.630 ($R^{2}=0.493$),\;Y = 0.139X + 0.490 ($R^{2}=0.925$) for yield, and Y = -4.880X + 81.116 ($R^{2}=0.665$) for head rice. When leaves were cut after the heading of rice, it was Y = -23.0l4X + 83.589 ($R{2}=0.915$), for grain maturity, Y=0.141X + 3.466 ($R^{2}=0.842$) for yield, and Y = -13.795X + 81.964 ($R^{2}=0.898$) for head rice. We found that when leaf cutting after the heading stage caused more damage than before the heading in terms of yield and yield components. Based on theses results the economic threshold level was estimated to be 30% and 7% leaf loss before and after heading stage.