• Molecules and Cells
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• v.27 no.4
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• pp.443-447
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• 2009

This paper reports on the structural rearrangement of satellite DNA type I repeats and heterochromatin during the dedifferentiation and cell cycling of mesophyll protoplasts of cucumber (Cucumis sativus). These repeats were localized in the telomeric heterochromatin of cucumber chromosomes and in the chromocenters of interphase nuclei. The dramatic reduction of heterochromatin involves decondensation of subtelomeric repeats in freshly isolated protoplasts; however, there are not a great many remarkable changes in the expression profile. In spite of that, reformation of the chromocenters, occurring 48 h after protoplast isolation, is accompanied by recondensation of satellite DNA type I; however, only partial reassembly of these repeats was revealed. In this study, FISH and a flow cytometry assay show a correlation between the partial chromocenter and the repeats reassembly, and with the reentry of cultivated protoplasts into the cell cycle and first cell division. After that, divided cells displayed a higher variability in the expression profile than did leaves' mesophyll cells and protoplasts.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.205-213
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• 2022

The experimental fish transplanted from China in 2015 was used after seedling production and cultivated. Breeding management for experiment was carried out from October 2020 to February 2021. Also, it succeeded in inducing artificial maturation three to four months earlier than wild broodstock and secured good quality fertilized eggs. The average size of fertilized eggs was 1.22 mm, at 20℃ Blastodisc (15 minutes post-fertilization), 2 cell (50 minutes), 4 cell (1 hours), 8 cell (2 hours), 16 cell (2 hours and 30 minutes), 32 cell (2 hours and 50 minutes), morula (3 hours), blastula (8 hours), gastrula (15 hours), skull formation (20 hours), organ formation (30 hours) and hatching yolk larvae stage (35 hours). The total length of the just hatched larvae were 2.50 ± 2 mm, and then gain growth of 42.5 mm by 60 days, reaching 45 ± 5 mm.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.374-386
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• 2022

Phytoplankton communities, with emphasis on picoplankton and nanoplankton, were investigated in Gamak Bay, South Korea, where freshwater input and coastal water intrusion shape ecosystem functions. Shellfish farms and fish farms are located in the inner bay and outer bay, respectively, and tides translocate uneaten food and urine production from aquaculture farms toward the inner bay. Water masses were distinctly different based on a significantly different density between the surface and bottom layer and among three water masses, including the inner bay, outer bay, and Yeosu Harbor. Phytoplankton communities were quantified using flow cytometry and size-fractionated chlorophyll-a (chl-a) was measured. Salinity was a principal variable separating phytoplankton communities between the surface and bottom layer, whereas Si(OH)₄ controlled the communities in the inner bay, and NH₄⁺ and PO₄^3- governed the outer bay communities. While phycocyanin-containing (PC) cyanobacteria dominated in the outer bay, phycoerythrin-containing (PE) cyanobacteria dominance occurred with cryptophyte dominance, indicating that nutrients affected the distribution of pico- and nanoplankton and that cryptophytes potentially relied on a mixotrophic mode by feeding on PE cyanobacteria. Interestingly, picoeukaryotes and eukaryotes larger than 10 ㎛ were mostly responsible for the ecological niche in the western region of the bay. Given that chl-a levels have historically declined, our study highlights the potential importance of increased small phytoplankton in Gamak Bay. Particularly, we urge an examination of the ecological role of small phytoplankton in the food supply of cultivated marine organisms.

• Journal of fish pathology
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• v.19 no.1
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• pp.7-15
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• 2006

Amyloodinium sp. was found on the gills of mullet (Mugil cephalus) cultured on land. No external symptoms in the diseased fish were found except decoloration of the gills. In fresh preparations of the gills the parasites were opaque round or oval shape with a bright nucleus and 43.5 ㎛ (18.2～72.7, n=20) in size. In preparations added a drop of Lugol solution, they were black with the same shapes in fresh preparations and 43.5 ㎛ (n=20) in size. The parasites were stained black and blue in a droplet of Lugol solution and Diff-Quick III solution, respectively and their sizes were a little larger than in wet preparations. After stained with May-Grunwald Giemsa, the parasites appeared granular eosinophlic in the peripheral cytoplasm and granular strong basophilic in the center. In silver impregnated specimens the peripheral granules were negative and the central ones positive. The granules appeared brown in purplish cytoplasm after staining with Lugol solution. The parasites developed by binary division when they were cultivated in filtered seawater at 20℃. Histopathologically severe epithelial hyperplasia and fusion in the gill filaments resulted in clubbing, especially the proximal region of the filament. Epithelial hyperplasia was also found in the basal regions of the gill filaments and some epithelial cells were occasionally detached from the filaments. Some pear-shaped trophonts of the parasites with rhizoid attached on the gill filaments showing hyperplasia of the epithelial cells and mucous cells.

• Journal of fish pathology
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• v.26 no.3
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• pp.303-310
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• 2013

Since March in 2013, Inland Aquaculture Research Center, NFRDI has cultivated 1,000 wild swamp eel(Monopterus albus) for species conservation research. While cultivating, 100 fishes showed clinical sign that darkness color, mucus hypersecretion and anus rubor. Even some of them were died. Result of anatomical test, all 100 fishes were infected with intestinal parasite, acanthocephalan. So we were going to determine the case of acanthocephalans infection in swamp eel(Monopterus albus) as histopathologically. Acanthocephalan was founded in alimentary canal only. Parasite were confirmed 19 unit in individual fish, averagely. Heavy infected fishes were confirmed enterocleisis by acanthocephalans. Worms were attachment in submucosa layer of alimentary canal by invading proboscis. Characteristic symptoms were observed in stomach and intestine, including hyperemia in mucous epithelium, infiltration of eosinophills in submucosa layer, inflammation, parasitic granuloma. Some fishes showed vacuolization of gastricgland epithelium, necrosis of intestinal mucosa. Other organs, excluding alimentary canal, were not found lesion. The results of this study, the effect of the acanthocephalan infection on swamp eel(Monopterus albus) could find and it seems to be a big help in the future swamp eel(Monopterus albus) cultivation.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.3
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• pp.23-31
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• 2018

This study was carried out to investigate the effects of livestock manure compost and fish-meal liquid fertilizer on the growth of cucumber and the soil properties for the stable production of organic cucumber. Cucumber was transplanted in greenhouse on the $6^{th}$ of April in 2017, and this experiment contained five treatments: livestock manure compost 100% (LC 100%), livestock manure compost 50% + fish-meal liquid fertilizer 50% (LC50 + LF50), livestock manure compost 50% (LC50), chemical fertilizer (NPK), and no fertilizer (NF). As a result, it was shown that soil chemical properties of LC50 + LF50 plot is not different from that of LC100 plot except for the EC content, but soil chemical properties of LC50 + LF50 plot is statistically significantly different from that of NPK plot except for pH. As a result of evaluating the functional diversity of soil microbial communities using Biolog system, the substrate richness (S) and the diversity index (H) were the highest in LC50 + LF50 plot. As a result of comparing the cucumber growth and yield, it was found that there was no statistically significant difference between the plant height and the fresh weight of LC100, LC50 + LF50, and NPK plot, but the plant height and the fresh weight of LC100, LC50 + LF50, and NPK plot were different from that of LC50 and NF plot. The yield of cucumber was the highest in NPK plot r(7,397 kg/10a), but there was no statistically significant difference in the yield of cucumber between NPK plot and LC100, LC50 + LF50 plot. The above-described results suggested that the livestock manure compost and fish meal liquid fertilizer can be used for organic cucumber production under greenhouse condition.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.2
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• pp.147-161
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• 2011

Korea is surrounded by sea on three sides. This country has been supplied with a variety of aquaculture products cultivated on shores. There have recently been a lot of studies to have better understanding of the correct location and quantity of aquaculture farms for seaweed, ear shells and fish that cover a wide area of sea. And it is necessary to use the geographic information system and remote sensing to detect the aquaculture farms in order to effectively manage them. This study uses higher resolution aerial images(25 centimeters) than satellite images of 2~2.5-meter resolution that have been ever used, to conduct an accuracy detection of aquaculture farming facilities. It chooses as the case study area the Wando region that has aquaculture farms for seaweed, ear shells and fish. Aerial photos of the island were obtained in this study and an image correction of them was conducted. A spatial database was then constructed in this study and the detection of aquaculture farming facilities was performed. An analysis of facilities inside and outside the permitted areas reveals that there has been an increase in the facilities of seaweed and ear shell aquaculture farms outside the permitted areas. And also it tells that because the facilities of fish aquaculture farms have turned into those of ear shell aquaculture farms, there has been a decrease in permitted facilities, facilities detected on the basis of aerial images, and facilities outside the permitted area. It will be necessary to continuously control and manage the unpermitted facilities, regarding the increase in the facilities inside and outside the permitted area for seaweed and ear shell aquaculture farms. Because the facilities of aquaculture farms cover a wide range of areas(sea) in this manner, it is more effective to depend on high resolution aerial images than a field survey to detect and calculate the facilities. This study comes up with a plan for using aerial images to detect the location and the quantity of the fish aquaculture facilities and then effectively manage them.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.340-360
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• 1982

Because of the continuing rapid increase in pesticide usage in Taiwan, much attention has been focus on pesticide contamination of food and effect of pesticides on human and environmental health. The Plant Protection Center (PPC) conducts safety evaluation of pesticides usee! in Taiwan. The pesticides are classified into different groups based on their acute toxicities. Pesticides which are classified into extremely toxic group are not allow to used on short term crops or the continuously harvest crops. The acute toxicity of pesticides to the beneficial insects are also studied, special attention has been paid to the two predators of rice brown planthopper. 60% of cultivated land in Taiwan are paddy field; therefore, acute fish toxicity was taken into consideration when a pesticide was applied for registration to be used in the paddy. Fish toxicities were evaluated by the dangerous rating value which is the amount of pesticide residue in the field water over the TLM value. Mutagenicity of pesticides was continuously evaluated by using Arne's microbial testing method. Island wide survey of residual levels of pesticides of known pollutants such as chlorinated hydrocarbon . insecticides, mercurial compounds in soil, water and biological samples were carried out constantly. The potential of a new1y Imported esticides to pollute the environment were studied by using model ecosystem. Ecological magnification (EM) of a chemical was calculated from model ecosystem. A chemical was considered as a pollutant when its EM value over 5000. In order to ensure the levels of pesticides residue of the crop within the safety limit. The 'tolerance' of pesticides on different crop groupings were established base on 1) acceptable daily intake value of individual pesticides, 2) average daily consumption of each crop groupings by Chinese person, 3) Actual residues of pesticides. on different crops obtained from supervised trials. Total about 79 pesticides for which the tolerances have been established on different crop groupings. Because the intensive agricultural system was adopted in Taiwan. The phytotoxicity of pesticides to the non-target crops was therefore become one of the important factor in the safety evaluation of pesticide usage. These will include 1) direct injury, 2) injury caused by pesticide polluted irrigation water, 3) injury caused by the pesticide polluted soil, 4) reduction of growth caused by the effect of pesticide on the soil microorganisms. This paper will reviewed all the aspects mentioned in the previous .paragraphs. Most the works have done in Taiwan by the PPC.y the PPC.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.325-331
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• 2010

Attractiveness of stink bugs to various colors, heights and locations of fish-net traps incorporated with aggregation pheromones was determined. Bean bug, Riptortus pedestris Fabricius, was most attracted to yellow color trap, followed by white, black, green, blue and brown. R. pedestris and one-banded stink bug, Piezodorus hybneri Gmelin, were most attracted to fish-net traps placed 80 cm above the ground regardless of sexes of two species of stink bugs. Between the sexes, however, R. pedestris females were more attracted to 40 and 80 cm above the ground than the males at those heights although the attraction was not significantly different at 120 and 160 cm heights. P. hybneri females tended to be attracted to 40 and 80 cm height traps but the attraction was the opposite at 120 and 160 cm heights. The highest attraction of R. pedestris was observed in a perilla field with no significant difference in the soybean field and border area in which no crop were cultivated between the perilla and soybean fields. R. pedestris was also more attracted to the sweet persimmon orchard than the soybean and medicinal crops fields, which was a significant difference between the two fields.

• Korean Journal of Medicinal Crop Science
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• v.5 no.2
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• pp.131-138
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• 1997

Campanulaceae having the most growing areas among medicinal crops cultivated in Korea occasionally failed to establish a reasonable standing in practice. The experiment was carried out to examine the effect of prechilling (0 : 4 : 8 days), light quality (red : white : dark) and daily irradiation hours (8 : 12 : 16) after sowing on seed germination and radicle elongation of Campanulaceae (Platycodon grandiflorum : Codonopsis lanceolata : C. pjlosula) to give an information on their earlier standing establishment. Mean germination rate of P. grandiflorum was the highest but that of C. pilosula was the lowest regardless of all the treatments. 12 hours irradiation or prechilling increased to 8 days enhanced their earlier or later germination, respectively. White light increased the rate of P. grandiflorum but alleviated that of C. lanceolata regardless of the daily irradiation hours. Although prechilling eliminated such effect of white light, light quality treatment effect on their mean germination rates was influenced by period after sowing, daily irradiation hours or prechilling. On the 9th day after sowing, C. lanceolata showed the greatest radicle length, and both daily 8 hours irradiation and 8 days prechilling enforced to elongate their radicles, while P. grandjflorum and C. lanceolata more lengthened their radicles in all prechilling treatments than in no chilling but C. pilosula showed the similar result only in the 8 days prechilling.