• Journal of the Korean Geographical Society
• /
• v.42 no.3 s.120
• /
• pp.344-354
• /
• 2007

Estuarine wetlands for 33 watersheds in the Han River estuary were delineated on topographic maps from the 1910s, 1970s, and 2000s. Then, these data were used to address the issue of spatial distribution and temporal variation. Watershed characteristics such as drainage density, location, watershed size, slope, and elevation were identified for each watershed to determine the relationship between watershed characteristics and spatial distribution of estuarine wetlands. The analysis of estuarine wetlands indicated that wetlands in the estuary had declined gradually between the 1910s and the 1970s, although most wetlands were lost since the 1970s mainly caused by the large development projects related to urban expansion in metropolitan Seoul. The sediment composition and formation processes of the wetlands differed with watershed location; mud flats dominate in the lower part of the estuary, and relatively more sandy and emergent-plant wetlands occur near the main channel and tributaries of the Han River. Relatively more estuary wetlands occur in large watersheds, which have high slopes and low elevations. Estuarine wetlands have been lost dramatically in the densely populated watershed regions (i.e., Han River Seoul, Han River Goyang, West Han River), while relatively more wetlands have remained in undeveloped regions, including the Lower Imjin River and Lower Han River. In particular, anthropogenic disturbance has played an important role in the loss of wetland through the conversion of wetland into agricultural and developed land.

• Journal of Radiation Protection and Research
• /
• v.20 no.2
• /
• pp.79-83
• /
• 1995

A number of investigators have reported formation of radiolytic ultrafine particles produced by the interaction of ionizing radiation with atmospheric trace gases. Previous studies have suggested that a very high localized concentration of the hydroxyl radical produced by the radiolysis of water can react with atmospheric trace gases such as $SO_2$ and produce lower vapor pressure compounds that can subsequently nucleate. To determine the trace gas and water vapor concentration dependence of the active, positively charged, first decayt product of radon (Po-218), a well-controlled radon chamber was used in this research. The mobility spectrum of the decay products in the range of $0.07-5.0cm^2/V\;sec$ from the radon chamber was measured using alpha track detector installed inside a specially-designed electrostatic spectrometer. Measurements were taken for different concentrations (0.5ppm to 5ppm) of $SO_2$ in Purified, Compressed air. A kinetics Study following the clustering of $SO_2$ around the $PoO_x^+$ ion in an excess of $SO_2$ for interpretation of the reaction processes was performed.

• Proceedings of the Ginseng society Conference
• /
• 1984.09a
• /
• pp.21-26
• /
• 1984

The balance between metabolic activation of xenobiotics and detoxification of their active metabolites may playa vital role in controlling mutagenic and carcinogenic processes. To assess the possible role of P. ginseng C.A. Meyer in detoxification of xenobiotics, we studied the effects of ginseng on several parameters of the monooxygenasd system, including benzo(a) pyrene monooxygenase(AHH) and benzo(a) pyrene epoxide hydratase(EH) as well as effects of ginseng on the conjugation system. Test animals receiving ginseng saponin-fraction induced epoxide hydratase activity to over $150\%$ (20mg/kg b.w.) of the control and increased glutathione transferase activity (GSH-T) up to $140\%$ (20mg/kg b.w.) of the control, whereas no significant changes were observed in the benzopyrene monooxygenase activity (AHH). Such a selective induction of the inactivation enzyme epoxide hydratase, combined with a marked elevation of the detoxifying enzyme glutathione transferase, without a concurrent induction of benzopyrene monooxygenase which is responsible for the formation of carcinogenic intermediates, demonstrates that ginseng has the potential to alter the metabolic course of carcinogenic polycyclic aromatic hydrocarbons, and thereby enhance detoxification. Thus, ginseng may play an important role in the prevention of tumors caused by carcinogens.

• 한국균학회소식:학술대회논문집
• /
• 2014.10a
• /
• pp.11-11
• /
• 2014

Fungal pathogens have huge impact on health and economic wellbeing of human by causing life-threatening mycoses in immune-compromised patients or by destroying crop plants. A key determinant of fungal pathogenesis is their ability to undergo developmental change in response to host or environmental factors. Genetic pathways that regulate such morphological transitions and adaptation are therefore extensively studied during the last few decades. Given that epigenetic as well as genetic components play pivotal roles in development of plants and mammals, contribution of microbial epigenetic counterparts to this morphogenetic process is intriguing yet nearly unappreciated question to date. To bridge this gap in our knowledge, we set out to investigate histone modifications among epigenetic mechanisms that possibly regulate fungal adaptation and processes involved in pathogenesis of a model plant pathogenic fungus, Magnaporthe oryzae. M. oryzae is a causal agent of rice blast disease, which destroys 10 to 30% of the rice crop annually. Since the rice is the staple food for more than half of human population, the disease is a major threat to global food security. In addition to the socioeconomic impact of the disease it causes, the fungus is genetically tractable and can undergo well-defined morphological transitions including asexual spore production and appressorium (a specialized infection structure) formation in vitro, making it a model to study fungal development and pathogenicity. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Histone modifying enzymes were identified applying a search pipeline built upon profile hidden Markov model (HMM) to proteomes. The database incorporates 22,169 histone-modifying enzymes identified from 342 species including 214 fungal, 33 plants, and 77 metazoan species. The dbHiMo provides users with web-based personalized data browsing and analysis tools, supporting comparative and evolutionary genomics. Based on the database entries, functional analysis of genes encoding histone acetyltransferases and histone demethylases is under way. Here I provide examples of such analyses that show how histone acetylation and methylation is implicated in regulating important aspects of fungal pathogenesis. Current analysis of histone modifying enzymes will be followed by ChIP-Seq and RNA-seq experiments to pinpoint the genes that are controlled by particular histone modifications. We anticipate that our work will provide not only the significant advances in our understanding of epigenetic mechanisms operating in microbial eukaryotes but also basis to expand our perspective on regulation of development in fungal pathogens.

• 한국균학회소식:학술대회논문집
• /
• 2014.10a
• /
• pp.15-15
• /
• 2014

Fusarium graminearum (teleomorph Gibberella zeae) is an important plant pathogen that causes head blight of major cereal crops such as wheat, barley, and rice, as well as causing ear and stalk rot on maize worldwide. Plant diseases caused by this fungus lead to severe yield losses and accumulation of harmful mycotoxins in infected cereals [1]. Fungi utilize spore production as a mean to rapidly avoid unfavorable environmental conditions and to amplify their population. Spores are produced sexually and asexually and their production is precisely controlled. Upstream developmental activators consist of fluffy genes have been known to orchestrate early induction of condiogenesis in a model filamentous fungus Aspergillus nidulans. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we characterized functions of the F. graminearum fluffy gene homologs [2]. We found that FlbD is conserved regulatory function for conidiogenesis in both A. nidulans and F. graminearum among five fluffy gene homologs. flbD deletion abolished conidia and perithecia production, suggesting that FlbD have global roles in hyphal differentiation processes in F. graminearum. We further identified and functionally characterized the ortholog of AbaA, which is involved in differentiation from vegetative hyphae to conidia and known to be absent in F. graminearum [3]. Deletion of abaA did not affect vegetative growth, sexual development, or virulence, but conidium production was completely abolished and thin hyphae grew from abnormally shaped phialides in abaA deletion mutants. Overexpression of abaA resulted in pleiotropic defects such as impaired sexual and asexual development, retarded conidium germination, and reduced trichothecene production. AbaA localized to the nuclei of phialides and terminal cells of mature conidia. Successful interspecies complementation using A. nidulans AbaA and the conserved AbaA-WetA pathway demonstrated that the molecular mechanisms responsible for AbaA activity are conserved in F. graminearum as they are in A. nidulans. F. graminearum ortholog of Aspergillus nidulans wetA has been shown to be involved in conidiogenesis and conidium maturation [4]. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidia dormancy by suppressing microcycle conidiation in F. graminearum. In A. nidulans, FlbB physically interacts with FlbD and FlbE, and the resulting FlbB/FlbE and FlbB/FlbD complexes induce the expression of flbD and brlA, respectively. BrlA is an activator of the AbaA-WetA pathway. AbaA and WetA are required for phialide formation and conidia maturation, respectively [5]. In F. graminearum, the AbaA-WetA pathway is similar to that of A. nidulans, except a brlA ortholog does not exist. Amongst the fluffy genes, only fgflbD has a conserved role for regulation of the AbaA-WetA pathway.

• Journal of the Korean association of regional geographers
• /
• v.8 no.3
• /
• pp.295-313
• /
• 2002

While the growth of Taegu has occurred through the land readjustment project, the public sector development project and the construction of roads, its growth pattern has been shaped by physical constraints such as mountains, streams and rail roads. The processes of urban growth of Taegu are classified into four stages: the stage of urban embryo in the Chosun Era; the formation stage of the basic urban system after the Japanese Colonial Era up to 1960; the stage of urban growth in the industrialization period from 1960s to 1980; and lastly, the stage of urban expansion and maturation, with construction of extensive newly developed districts, after the 1980s. Since its promotion to a metropolitan city with the inclusion of Seongseo, Wolbae, Gosan, Ansim and Chilgok in 1981, those regions have grown into newly developed residential districts, with its accompanying high density and high rise apartments complexes, through the public sector development project. These newly developed districts are located about six to seven kilometers away from CBD of the city along with main radial roads. The sites are also located on the route of the fourth belt way of the city. While the Sangin, Seongseo and Jisan Beommul newly developed districts have developed contiguously with the existing built-up areas, the Siji and Chilgok districts have developed separately by the green belt and the Geumho River, respectively.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.54-54
• /
• 2003

Prostate gland contains neuroendocrine cells (PNECs) are playing important roles in physiological and pathophysiological processes of the prostate gland. Here, we investigated the role of purinoceptors in PNECs freshly isolated from rat ventral prostate (RPNECs) that show immunoreactivity to chromogranin A. Fura-2 ratiometry revealed that ATP evokes both fast Ca$\^$2+/ influx and store Ca$\^$2+/ release in RPNECs. A whole-cell patch clamp study demonstrated fast inactivating cationic current activated by ATP or by ${\alpha}$,${\beta}$-MeATP, which was blocked by ATP-TNP. The activation of P2X inward current was tightly associated with a sharp increase in [Ca$\^$2+/]$\sub$c/. The presence of P2X1/3 subtypes were proved by RT-PCR analysis. For the stored Ca$\^$2+/ release, ATP and UTP showed similar effects, suggesting the dominant role or P2Y2 subtypes, also confirmed by RT-PCR. Both P2X (${\alpha}$,${\beta}$-MeATP) and P2Y (UTP) stimulation induced changes in the cell morphology (initial shrinkage and blob formation on the surface) reversibly. Exocytotic membrane trafficking events were monitored with the membrane-bound fluorescent dye, FM1-43 using confocal microscopy. In spite of the similar Ca$\^$2+/ responses, UTP was far less effective in triggering exocytosis than ${\alpha}$,${\beta}$ -MeATP. Since serotonin is reportedly stored in the secretory granule of PNECs, we directly examined whether the aforementioned agonists elicit release of serotonin using carbon fiber electrode-amperometry. In accordance with the results of FM1 -43 experiments, ${\alpha}$,${\beta}$-MeATP efficiently evoke serotonin secretion while not with UTP. In summary, the P2X-mediated Ca$\^$2+/ influx plays crucial roles in the exocytosis of RPNECs. Although a global increase in [Ca$\^$2+]$\sub$c/ might be related with the morphological changes, a sharp rise of [Ca$\^$2+/]$\sub$c/ in the putative sub-plasmalemmal ‘microdomains’ might be a decisive factor for the exocytosis.

• The Journal of Fisheries Business Administration
• /
• v.25 no.2
• /
• pp.1-46
• /
• 1994

The Purpose of this research is to analyze and discuss the development of yellowtail aquaculture industry in Japan and its management structure. The research includes the following : (a) It confirms the industrial conditions of yellowtail aqaculture which has a national technical and mass production system that has been developed at great speed. (b) It analyzes yellowtail aqaculture development from a family - oriented management to a large scale production. (c) It examines how the fisheries cooperatives harmonized their role with the object of individual aqaculture management and aqaculture fishing ground management. The reasons for this study focusing on the yellowtail aqaculture industry of Japan are : (a) The yellowtail aqaculture is regared as a typical field in aqaculture because it reflects the general aqaculture history, quantity of fisheries aqaculture product, the number of fishermen involved in this industry, technology , and the live and fish market formation in Japan. (b) The aqaculture has the most powerful entrepreneurial in financial and management style. The aqaculture industry also has a most individual management style which includes planned production and shipping strategy. This research has attempted to study the industrial processes of fisheries aqaculture industry and its management development, and focused on the yellowtail aqaculture industry of Japan. This work also includes data about the aqaculture management of fisheries cooperatives and case by case analysis of aqaculture production. The following results were obtained from this study : First, even though ocean, weather conditions, and widespread propagation of places suitable for aqaculture in Japan were crucial factors in aqaculture development, it must be pointed out that fisheries policy in Japan changed from "catching" in the 1960s to "cultivating". Second, the widespread course of fisheries cultivating technology in Japan has had two characteristics. One is that early aqaculture technology spread to the southern part of Japan and the other is that the metal nets were widely used in the northern part in the 1970s. Japan's yellowtail aqaculture industry's overproduction was due to metal nets. However, the use of mwtal nets also contributed to the improvement of aqaculture and the strategic aspects of aqaculture management. In addition, it should be stressed that Kagoshima prefecture as the pioneer of metal nets contributed to fisheries aqaculture development in japan. Third, as aqaculture technology developed, entrepreneurial qualities of aqaculture management also developed this field into a large scale business. Even though it is not clear, large scale management of yellowtail aqaculture shows evidence of superiority over small andmedium - size management of yellowtail aqaculture. Fourth, yellowtail aqaculture management in Japan hascontributed to the production system and aqaculture strategy to meet consumers' needs and market demands from weather - oriented trational fisheries industry, which overcame their overproduction structure. Fifth, Japanese fisheries cooperative played very important roles in the prevention of fishing grounds production from destruction and in promoting suitable aqaculture facilities so that aqaculture could grow continually.ld grow continually.

• Clinical and Experimental Reproductive Medicine
• /
• v.26 no.2
• /
• pp.193-201
• /
• 1999

In this study we determined fertilization processes and developmental ability of porcine oocytes following injection of round spermatid in the presence of artificial activation. Electrical stimulation at 3 h before spermatid injection significantly increased the incidence of normal fertilization as compared to those following injection without stimulation or with stimulation immediately after injection. The incidences of two pronuclear formation and apposition were not different in oocytes between following intracytoplasmic spermatid and spermatid nucleus injection. Indirect immunocytochemistry and laser scanning confocal microscopy study revealed that micro tubules were organized from the oocyte cortex following round spermatid injection, and this seemed to move both male and female pronuclei into the oocyte center. Paternal mitochondria which are introduced with spermatid have been observed up to 4-cell. Our study indicated that either round spermatid or it's nucleus can be used to produce viable bovine embryos by injection into unfertilized oocytes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.2
• /
• pp.306-310
• /
• 2005

The comparison in release rate constant and properties of extracts from extruded raw ginseng and extruded white ginseng was conducted to apply extrusion process for manufacturing of released ginseng tea bag. Dry raw ginseng and white ginseng powder were extruded at 20∼30% moisture content and 200∼300 rpm by using an experimental twin-screw extruder. Browness and redness (both indicated the releasing of saponin and ginsenosides) were increased with the increase in the screw speed and the decrease of moisture content. Crude saponin and water solubility index (WSI) of both ginseng also share the same behaviour against the level of screw speed and moisture content, as well as browness and redness. The particle size effects of extruded raw ginseng at 20% and 28% moisture content on absorbance of released extract at 260 up to 560 nm, WSI, and water absorption index were determined. While particle size decreased from 800∼1000 nm to 200∼500 nm, absorbance and WSI are decreased. Absorbance and WSI shown increasing level while moisture content was decreased. In conclusion, the formation of pores by expansion and disruption of cell wall in extrusion cooking were obviously responsible to increase the amount of released extract of extruded ginseng and its WSI as well. The extrusion process turns out be the efficient process for manufacturing of commercial ginseng tea product than those of other thermal processes.