• Title/Summary/Keyword: 뽕나무이

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Potassium Physiology of Upland Crops (밭 작물(作物)의 가리(加里) 생리(生理))

  • Park, Hoon
    • Korean Journal of Soil Science and Fertilizer
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    • v.10 no.3
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    • pp.103-134
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    • 1977
  • The physiological and biochemical role of potassium for upland crops according to recent research reports and the nutritional status of potassium in Korea were reviewed. Since physical and chemical characteristics of potassium ion are different from those of sodium, potassium can not completely be replaced by sodium and replacement must be limited to minimum possible functional area. Specific roles of potassium seem to keep fine structure of biological membranes such as thylacoid membrane of chloroplast in the most efficient form and to be allosteric effector and conformation controller of various enzymes principally in carbohydrate and protein metabolism. Potassium is essential to improve the efficiency of phoro- and oxidative- phosphorylation and involve deeply in all energy required metabolisms especially synthesis of organic matter and their translocation. Potassium has many important, physiological functions such as maintenance of osmotic pressure and optimum hydration of cell colloids, consequently uptake and translocation of water resulting in higher water use efficiency and of better subcellular environment for various physiological and biochemical activities. Potassium affects uptake and translocation of mineral nutrients and quality of products. potassium itself in products may become a quality criteria due to potassium essentiality for human beings. Potassium uptake is greatly decreased by low temperature and controlled by unknown feed back mechanism of potassium in plants. Thus the luxury absorption should be reconsidered. Total potassium content of upland soil in Korea is about 3% but the exchangeable one is about 0.3 me/100g soil. All upland crops require much potassium probably due to freezing and cold weather and also due to wet damage and drought caused by uneven rainfall pattern. In barley, potassium should be high at just before freezing and just after thawing and move into grain from heading for higher yield. Use efficiency of potassium was 27% for barley and 58% in old uplands, 46% in newly opened hilly lands for soybean. Soybean plant showed potassium deficiency symptom in various fields especially in newly opened hilly lands. Potassium criteria for normal growth appear 2% $K_2O$ and 1.0 K/(Ca+Mg) (content ratio) at flower bud initiation stage for soybean. Potassium requirement in plant was high in carrot, egg plant, chinese cabbage, red pepper, raddish and tomato. Potassium content in leaves was significantly correlated with yield in chinese cabbage. Sweet potato. greatly absorbed potassium subsequently affected potassium nutrition of the following crop. In the case of potassium deficiency, root showed the greatest difference in potassium content from that of normal indicating that deficiency damages root first. Potatoes and corn showed much higher potassium content in comparison with calcium and magnesium. Forage crops from ranges showed relatively high potassium content which was significantly and positively correlated with nitrogen, phosphorus and calcium content. Percentage of orchards (apple, pear, peach, grape, and orange) insufficient in potassium ranged from 16 to 25. The leaves and soils from the good apple and pear orchards showed higher potassium content than those from the poor ones. Critical ratio of $K_2O/(CaO+MgO)$ in mulberry leaves to escape from winter death of branch tip was 0.95. In the multiple croping system, exchangeable potassium in soils after one crop was affected by the previous crops and potassium uptake seemed to be related with soil organic matter providing soil moisture and aeration. Thus, the long term and quantitative investigation of various forms of potassium including total one are needed in relation to soil, weather and croping system. Potassium uptake and efficiency may be increased by topdressing, deep placement, slow-releasing or granular fertilizer application with the consideration of rainfall pattern. In all researches for nutritional explanation including potassium of crop yield reasonable and practicable nutritional indices will most easily be obtained through multifactor analysis.

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A Study on the History and Species of Street Trees in Seoul (서울시 가로수 역사와 수목 고찰)

  • Song, Suk-Ho;Kim, Min-Kyung
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.38 no.4
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    • pp.58-67
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    • 2020
  • The present study was conducted as part of basic research for selecting species of street trees with historical value in Seoul. It also made up a list of traditional landscape trees for a variety of alternatives. The following results are shown below. As to the history of street trees in Korea, records on to-be-estimated street trees are found in historical documents written in King Yangwon during the second year of Goguryeo Dynasty (546) and King Myeongjong during 27 year of Goryeo (1197). However, it is assumed that lack of clarity is found in historical records. During the 23 year of King Sejong in the early Joseon Dynasty (1441), the record showed that the state planted street trees as guideposts on the postal road. The records revealed that Ulmus spp. and Salix spp. were planted as guidance trees. The street tree system was performed in the early Joseon Dynasty as recorded in the first year of King Danjong document. Pinus densiflora, Pinus koraiensis, Pyrus pyrifolia var. culta, Castanea crenata, Styphnolobium japonicum and Salix spp. were planted along the avenue at both left and right sides. Morus alba were planted on streets during the five year of King Sejo (1459). As illustrated in pieces Apgujeong by painter Jeongseon and Jinheonmajeongsaekdo in the reign of King Yeongjo, street trees were planted. This arrangement is associated with a number of elements such as king procession, major entrance roads in Seoul, place for horse markets, prevention of roads from flood and indication. In the reign of King Jeongjo, there are many cases related to planting Pinus densiflora, Abies holophylla and Salix spp. for king procession. Turning king roads and related areas into sanctuaries is considered as technique for planting street trees. During the 32 year of King Gojong after opening ports (1985), the state promoted planting trees along both sides of roads. At the time, many Populus davidiana called white poplars were planted as rapidly growing street trees. There are 17 taxa in the Era of Three Kingdoms records, 31 taxa in Goryeo Dynasty records and 55 taxa in Joseon Dynasty records, respectively, described in historical documents to be available for being planted as street trees in Seoul. 16 taxa are recorded in three periods, which are Era of Three Kingdoms, Goryeo Dynasty and Joseon Dynasty. These taxa can be seen as relatively excellent ones in terms of historical value. The introduction of alien plants and legal improvement in the Japanese colonial period resulted in modernization of street tree planting system. Under the six-year street tree planting plan (1934-1940) implemented as part of expanding metropolitan areas outside the capital launched in 1936, four major street trees of top 10 taxa were a Populus deltoides, Populus nigra var. italica, Populus davidiana, Populus alba. The remaining six trees were Salix babylonica, Robinia pseudoacacia, platanus orientalis, Platanus occidentalis, Ginkgo biloba, and Acer negundo. Beginning in the mid- and late 1930s, platanus orientalis, Platanus occidentalis were introduced into Korea as new taxa of street trees and planted in many regions. Beginning on 1942, Ailanthus altissima was recommended as street trees for the purpose of producing silks. In 1957 after liberation, major street tree taxa included Platanus occidentalis, Ginkgo biloba, Populus nigra var. italica, Ailanthus altissima, Populus deltoides and Salix babylonica. The rank of major street tree species planted in the Japanese colonial period had changed. Tree planting trend around that period primarily representing Platanus occidentalis and Ginkgo biloba still holds true until now.

Studies on the Relationship between Silkworm Rearing and Tobacco Cultivation I. Tobacco Field Cultivated in Mulching System Affecting the Silkworm Rearing in Autumn Season (연초재배가 양잠에 미치는 영향에 관한 연구 I. 뽕밭 부근의 담배개량 Mulching 재배가 추잠작에 미치는 영향에 관한 시험)

  • 정태암;이상풍;김정배;홍기원;김계명;마영일
    • Journal of Sericultural and Entomological Science
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    • v.17 no.2
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    • pp.141-149
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    • 1975
  • Silkworm is known to be damaged under the unfavorable environmental conditions. Recently, it has been often argued that nicotine is a main factor to affect the silkworm nutritional balance and to result in decrease of quantitative characters, and unbalance of larval nutrition. Especially in spring season, there is tendency to produce nicotine damage to silkworm fed with the mulberry leaf near to tobacco field early cultivated in mulching system. In these connections, the trial was made in the different pots placing by the different distance 10rn, 20m, 40m, and 60m in the direction of east-north from the tobacco field. Location of pot near to the tobacco fold is 40m below the tobacco Held and gradually higher than the tobacco field by 10 degree of slope. In addition, when the mulberry field is divided into two areas from the east-south to west-north, southern east zone is lowering down below 10 degree of slope and has 36% of east-south wind, 21% of south-east wind and 16% of south wind, etc. Pots are left on the mulberry field from the completion of lower part leaf harvest to just before upper part leaf harvest is completed for 32 days. Then silkworm at 4th-5th stage was fed with the leaf grown during the period and larval characters are statistically analyzed. The results are summarized as follows: 1. 10-40m distant pot statistically at the same level has the longest larval duration and 60m distant pot is. not significant at 5% level. Whole larval duration has same tendency as in the 5th larval duration. 2. Percentage of delayed molting larvae at the 5th stage is increased in 10m distant pot and there is no significance statistically in other pots, as compared with that of control. 3. It is not showed that there is no damage to mortality of the old larvae in 60m distant pot. 4. 10-20m distant pot produces a low pupation and others are at the same level statistically at 5% significance, 5. It is showed that nicotine damage is occurred in single cocoon freight and cocoon shell weight up to 60m distant pot, rather higher damage in cocoon shell weight than in single cocoon weight. 6. It is showed that cocoon yield from 10, 000 molted larvae including double cocoon is decreased up to 40m distant pot far from the tobacco field in which 40% of cocoon yield in 10m distant pot by 7kg, 26% of cocoon yield in 20m distant pot by 3.9kg, 24% of cocoon yield in 40m distant pot by 3.6kg, and 12% of cocoon yield in 60m distant pot by 1.8kg, as compared with control. However, there is no significance statistically at 5% level in 60m distant pot. With these above results, it is concluded that nicotine da mage could be occurred in cocoon yield and cocoon quality up to 60m distant far from the tobacco field.

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Studies on tile Resources for the Artificial Diet and Feeding Response of the Silkworm, Bombyx mori (가잠의 인공사료자원과 섭식성에 관한 연구)

  • 김주읍
    • Journal of Sericultural and Entomological Science
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    • v.23 no.2
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    • pp.11-36
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    • 1982
  • Forty-nine plant species as additives to silkworm artificial diet and 5 species as cellulose sources for artificial diet were screened for their economic values as feed-resources for the silkworm. Feeding response to artificial diet was tested on 82 silkworm strains. The effect of rearing conditions on feeding response and enzyme activities in the silkworm was investigated. The results were summarized as follows. 1. Seven species out of 49, Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Alnus japonica Stendel, Trifolium repens L, Prunus serrulata Lindley. Var, Glycine max L increased feeding response, compared with the basic formula of artificial diet. 2. The economic values of Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Ainus japonica Stendel, Cassia tera L, Erigeron canedensis L as feed-resources for artificiale diet were recognized, through feeding experiment during the entire larval stage. 3. Mulberry cellulose showed the best results in rearing and cocoon characteristics. 4. The extent of feeding response varied according to strains and varieties. Varieties in japanese strains showed higher feeding response than those in chinese and european varieties, with considerable variations among a varieties in strains. 5. The begining of 4th instar seems to be a proper time to convert from mulberry to artificial diet, or artificial diet to mulberry, however the middle of 3rd instar seems acceptable. 6. The optimum temperature for artificial diet rearing is 30$^{\circ}C$ during the period of 1st-3rd instar and 28$^{\circ}C$ for 4th-5th instar. 7. Electrophoretic isozyme patterns of esterase and acid phosphatase on agarose gel, as affected by strain. rearing temperature and feed-resources, were observed as follow. (1) Isozyme patterns of mid-gut esterase varied, depending on instar. One or two more isozyme bands were observed in the larvae than feed on the mulberry fed for the artificial diet. (2) A strain, chinese-15 with a higher feeding response, had 1∼2 more bands than chinese-60 with a lower feeding response. (3) Five bands of mid-gut esterase in 3rd and 4th instar larvae reared at 28$^{\circ}C$. and 4 for 3rd instar and 6∼7 for 4th instar larvae at 35$^{\circ}C$ were observed. (4) No similar esterase bands could be found among mid-gut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. (5) There was rather small digerence in acid phosphatase types of mid-gut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd instar, two at 4th instar and three at 5th instar. In blood, one active band at 3rd or 4th instar and three bands at 5th inster wire detected.

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Ethanol Extracts of Mori Folium Inhibit Adipogenesis Through Activation of AMPK Signaling Pathway in 3T3-L1 Preadipocytes (3T3-L1 세포에서 상엽이 유발하는 AMPK signaling pathway를 통한 adipogenesis 억제에 관한 연구)

  • Ji, Seon Young;Jeon, Keong Yoon;Jeong, Jin Woo;Hong, Su Hyun;Huh, Man Kyu;Choi, Yung Hyun;Park, Cheol
    • Journal of Life Science
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    • v.27 no.2
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    • pp.155-163
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    • 2017
  • Mori Folium, the leaf of Morus alba, is a traditional medicinal herb that shows various pharmacological activities such as antiinflammatory, antidiabetic, antimelanogenesis, antioxidant, antibacterial, antiallergic, and immunomodulatory activities. However, the mechanisms of their inhibitory effects on adipocyte differentiation and adipogenesis remain poorly understood. In the present study, we investigated the inhibition of adipocyte differentiation and adipogenesis by ethanol extracts of Mori Folium (EEMF) in 3T3-L1 preadipocytes. Treatment with EEMF suppressed the terminal differentiation of 3T3-L1 preadipocytes in a dose-dependent manner, as confirmed by a decrease in the lipid droplet number and lipid content through Oil Red O staining. EEMF significantly reduced the accumulation of cellular triglyceride, which is associated with a significant inhibition of pro-adipogenic transcription factors, including sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator-activated receptor-${\gamma}$ ($PPAR{\gamma}$), and CCAAT/enhancer-binding proteins ${\alpha}$ ($C/EBP{\alpha}$) and ${\beta}$ ($C/EBP{\beta}$). In addition, EEMF potentially downregulated the expression of adipocyte-specific genes, including adipocyte fatty acid binding protein (aP2) and leptin. Furthermore, EEMF treatment effectively increased the phosphorylation of the AMP-activated protein kinase (AMPK) and acetyl CoA carboxylase (ACC); however, treatment with a potent inhibitor of AMPK, compound C, significantly restored the EEMF-induced inhibition of pro-adipogenic transcription factors and adipocyte-specific genes. These results together indicate that EEMF has preeminent effects on the inhibition of adipogenesis through the AMPK signaling pathway, and further studies will be needed to identify the active compounds in Mori Folium.

What Do Female Jobs Do for Women's Job Continuity? : Occupational Sex Segregation and Women's Job Exits in the U.S.

  • Min, Hyeon-Ju
    • Korea journal of population studies
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    • v.29 no.1
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    • pp.185-207
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    • 2006
  • Predominant explanations of the persistence of sex segregation ill occupations link job choices to profoundly gendered responses to childbearing and other family demands, arguing that women are more likely to seek jobs which are in some sense compatible with motherhood, either because they are family friendly (flexible, low intensity work) or because they are easy to exit and re-enter. In this paper, I examine the effect of occupational sex segregation on job exits into the labor market among women, with a special attention to the role of childbearing and child rearing. I use data from detailed employment histories gathered from the National Longitudinal Survey of Youth (NLSY) in continuous time event history models. My results indicate that women in female dominated jobs are less likely to exit their jobs than women in other types of occupations. Further this relationship is not shaped by motherhood. While mothers or pregnant women are more likely to leave work, mothers in female-dominated occupations are slightly less likely to leave employment than mothers in other occupations. These results are not consistent with the ideas that women's choice of female-dominated occupations expresses a gendered identity and women strategically seek jobs which accommodate maternal roles. Taken together, my findings do not provide support to the idea that women choose female-dominated occupations because they are easier to integrate with motherhood (except for the pregnancy period).

Possibility of establishment of a tree nursery at Saemangeum Reclaimed Land and Classification of 36 Landscape Trees Based on Salt Tolerance (새만금 간척지에서 36종 조경수의 양묘 가능성 검증과 내염성 분류)

  • Lee, Kyung Joon;Song, Jae Do;Lee, Kyu Hwa
    • Journal of Korean Society of Forest Science
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    • v.104 no.4
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    • pp.564-577
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    • 2015
  • The objectives of this study were to investigate the possibility of establishing a tree nursery at Saemangeum reclaimed land and to classify landscape trees based on the salt tolerance. A tree nursery (2.0 ha) was made in Gunsan Okgu area in 2012 with underground drain lines on the reclaimed land established in 2010. Salt content of the nursery soil within the 60 cm depth in 2013 was 5.13 dS/m and 8.20 dS/m for the pre-desalinated and non-desalinated lands, respectively. Thirty-six woody plant species (22 tree species and 14 shrub species at ages of 1 to 4) with a total of 3,943 individuals were planted in early April, 2013 and their growth performance was monitored until September of the same year. The average survival rate of the transplanted plants was 71.4% in late September, suggesting the high possibility of establishing a tree nursery at the reclaimed land. Based on the survival rate and tree vigor (amount of healthy leaves and crown development), the following 17 species with some salt tolerance were classified into three groups: "salt tolerant group" (3 species, Tamarix chinensis, Cudrania tricuspidata, Ilex serrata), "recommended group" (5 species, Pinus thunbergii, Albizia julibrissin, Ligustrum obtusifolium, Rosa rugosa, Pleioblatus pygmaeus), "plantable group" (9 species, Zelkova serrata, Hibiscus syriacus, Elaeagnus umbellata, Sorbus alnifolia, Sophora japonica, Metasequoia glyptostroboides, Quercus acutissima, Ulmus parvifolia, Robinia pseudoacacia). Seven tree species that had been adapted to the reclaimed land for three to four years before being transplanted to new reclaimed land in Gunsan Okgu area showed average survival rate of 98%, suggesting that pre-conditioned trees would survive well in the reclaimed land.

Amelioration of Plasma Glucose and Cholesterol levels in Db/db Mice by a Mixture of Chinese Herbs (Db/db 마우스 모델에 있어서 한약재조성물의 혈당 및 혈장 콜레스테롤 개선효과)

  • Lee, Jai-Heon;Cho, Chang-Woo;Han, Xiang-Fu;Hwang, Ji-Yeon;Kang, Min-Jung;Joo, Hee-Jeong;Kim, Mi-Eun;Seo, Yeong-Ju;Kim, Jung-In
    • Korean Journal of Medicinal Crop Science
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    • v.16 no.4
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    • pp.225-230
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    • 2008
  • Diabetes mellitus is the fifth leading cause of death among Koreans. Control of hyperglycemia and dyslipidemia is strongly correlated with decrease in risks for cardiovascular diseases, the most common and fatal diabetic complication. The effects of chronic feeding of a mixture of Chinese herbs on blood lipid profile were measured in an animal model of type 2 diabetes mellitus, db/db mice (C57BL/Ks). The Chinese herb mixture was composed of Panax ginseng C. A. Meyer,Astragalus membranaceus, Glycyrrhiza uralensis, Lycium chinense, Morus, Pueraria thunbergiana, Prunella vulgaris var. lilacina, Acanthopanax sessiliflorus, Schizandra chinensis, Scutellaria baicalensis, Dioscorea batatas, Polygonatum doratumvar. pluriflorum, Paeonia lactiflora, and Rehmannia glutinosa in a ratio of 1 : 0.7 : 0.4 : 0.7 :0.4 : 0.7 : 1.1 : 0.9 : 0.4 : 0.4 : 0.7 :0.7 : 0.9 : 0.9. Methanol extract of the Chinese herb mixture was tested for the inhibitory activity against yeast ${\alpha}$-glucosidase in vitro. The Chinese herb mixture extract inhibited ${\alpha}$-glucosidase by 25.2% at the concentration of 0.5mg/mL. Four weekold male db/db mice (n = 14) were fed AIN-93G semipurified diet or diet containing 10% powder of the Chinese herb mixture for 6 weeks after 1 week of adaptation period. Body weight (39.5 ${\pm}$ 1.6 g) and food intake (4.3 ${\pm}$ 0.6 g/day) of the Chinese herb group were not significantly different from those of the control group (40.4 ${\pm}$ 2.6 g and 4.5 ${\pm}$ 0.6 g/day). Consumption of Chinese herb mixture significantly decreased plasma glucose level (442.5 ${\pm}$ 36.0mg/dL) compared with the control group (489.8 ${\pm}$ 34.6 mg/dL, p < 0.05). Plasma cholesterol level (159.2 ${\pm}$ 18.4 mg/dL) of the Chinese herb group was significantly lower than that of the control group (185.4 ${\pm}$ 13.7 mg/dL, p < 0.05). Blood glycated hemoglobin (6.3 ${\pm}$ 0.8%) and plasma triglyceride levels (99.4 ${\pm}$ 15.0mg/dL) of the Chinese herb group were not significantly different from those of the control group (6.7 ${\pm}$ 0.7% and 108.8 ${\pm}$ 11.0mg/dL). Thus, the Chinese herb mixture could be useful in the treatment of diabetes and cardiovascular complications of diabetes.

Whitening activity of Ficus carica L. fruits extract through inhibition of tyrosinase and MITF expression (무화과(Ficus carica L.) 열매 추출물의 tyrosinase 및 MITF 발현 억제를 통한 미백 활성)

  • Min Ji Kim;Si Eun Park;Geun soo Lee;Jin Hwa Kim;Sunwoo Kwon;Hyung Seo Hwang
    • Journal of Applied Biological Chemistry
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    • v.66
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    • pp.204-212
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    • 2023
  • Whitening is inhibitory activity of the melanin synthesis of melanocytes. Recently, whitening materials have been developed on natural materials because of its side effects on skin. Figs (Ficus Carica L.) is a fruit belonging to the Moraceae family and whitening activity was reported in focusing on the fig's stem and leaf components, but whitening activity of the figs fruit was not known. Thus, in this study, we tried to observe its anti-melanogenesis as well as antioxidant and anti-inflammation. The radical scavenging activity of figs fruits extract (FFE) was observed as the level of 34.52±1.98%/60.71±1.26% compared to the control in the its maximum concentration in the DPPH/ABTS assay. Cytotoxicity of FFE was observed at 10% concentration by CCK8 assay, so the maximum concentration was set at 5% and applied to all experiments. FFE concentration dependently decreased NO production associated with inducible nitric oxide synthase, cyclooxygenase-2, interleukin-6 and tumor necrosis factor-α gene expression, these strongly suggesting anti-inflammatory activity. In melanin contents assay, FFE significantly down-regulated melanin production in α-MSH-stimulated B16F10 cell as well as tyrosinase inhibition in vitro. In addition, FFE decreased the Microphthalmia-associated transcription factor (MITF) mRNA expression about 94.34% compared to the α-MSH treatment group in RT-PCR. Finally, FFE significantly reduced the MITF, cAMP response element-binding protein and tyrosinase protein expression in the α-MSH stimulated B16F10 cell. Through these results, we found that FFE can not only directly inhibit tyrosinase enzyme activity but also suppress melanogenesis through regulation of MITF gene expression in α-MSH signal transduction.

Study on the Long-term Forecasting of Brown Planthopper Outbreaks (벼멸구 발생의 장기예찰을 위한 기초적 연구)

  • Paik Woon Hah;Paik Hyun Joon
    • Korean journal of applied entomology
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    • v.16 no.3 s.32
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    • pp.171-179
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    • 1977
  • Since the outbreak of the brown planthopper (Nilaparvata lugens) in 1915 caused tremendous losses in rice production, one of the more effective method of prevention of such a disaster could be the establishment of longterm forecasting system, In 1916 the author indicated there was a correlation between sunspot activities and brown planthopper and the white back planthopper outbreaks. However, the examples seem to be too small size to state a definite correlation. The purpose of the present study IS to revi~w the history of the brown planthopper outbreaks, and to establish a more effective forcasting system. The present forcasting methods are based on light trap catches of adults which already migrate into this country from mainland China. The regular cycle of 11.2 years of sunspot activity began in 1710, and was continued to present. To gather more records of brown planthopper, the author checked 'Joseon Wangjo Silrok' and analized the so-called 'Hwang' 'Hwang-chung' and 'Chung' which have multiple meanings, together with 'Samguk Sagi' 'Goryo Sa' and 'Munheon Bigo.' The results obtained by the about from review of these old literature citations revealed that ten species of insect and unknown species were involved: i. e., pine moth (Dendrolimus spectabilis), army worm (Mythimna separata), brown planthopper (Nilarvata lugens), white-back planthopper (Sogatella furcifera), migratory locust (Locutsa migratoria), rice stem borer (Chilo suppressalis,), mole cricket (Gryllotalpa africana), rice-plant weevil (Echinocnemus squameus), cut worm (Euxoa segetum), and mulberry pyralid Margaronia pyloalis) The suspected incidence of planthopper in old records expressed by 'Hwang' or 'Chung' revealed a total or 25 out of 37 in 'Samguk sagi,' 21 out of 49 in 'Goryo sa,' 9 of 73 in 'Wanjo-silrog,' and none of 8 in 'Munheon bigo' were planthoppers. Therefore, a total of 36 out of 167 records of insect incidence in the old literature can be possibly attributed to planthoppers. The brown planthopper and white-back planthopper migrate together to Korea every year from mainland China, However, the number of each species are differ by year. In 1975 outbreak the brown planthopper was dominant; and the white-back planthopper prevailed in 1946 and 1977 outbreaks, During the course of this study, the author was able to add a new record of outbreak of planthop per. In 1916 the white-back planthopper outbreak caused serious losses in Chungcheong-namdo and Jeonla-namdo, with losses estimated as high as 160 and 190 thousand seok (23.2 and 27.5 thousand M/T), in Naju and Secheon county, respectively. Since 1912, major outbreaks of brown planthopper or white-back planthopper have been recored 5 times. These occurrences coincide and well matched the period of minimum number of sunspots, With these authenticated records of planthoppers, the author believes there is a close correlation between brown planthopper and white-back planthopper outbreaks in Korea and sunspot activities. Therefore, in years of low number of sunspots, we should watch for and expect outbreaks of these. insects. At this time, it will be necessary to provide all possible prevention measures.

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