• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.231-237
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• 2012

Toxicity of $Ni^{2+}$ and Tebuconazole were investigated via FETAX (Frog Embryo Teratogenesis Assay-Xenopus) protocol using domestic frog embryos. Embryos of Black-spotted pond frog, Rana nigromaculata, were incubated and toxic effects of $Ni^{2+}$ and Tebuconazole were investigated by probit analysis. As a result, mortality and malformation rates were increased and larval body length was decreased in a dose dependant manner of $Ni^{2+}$ and Tebuconazole. The half maximal effective concentration ($EC_{50}$) of $Ni^{2+}$ and Tebuconazole were 0.07, $12.7mg\;L^{-1}$, respectively and the half maximal lethal concentration ($LC_{50}$) of $Ni^{2+}$ and Tebuconazole were 4.2, 39.1, respectively. The teratogenic index (TI) were 61.4 in $Ni^{2+}$ and 3.1 in Tebuconazole, respectively. These results reveals that $Ni^{2+}$ and Tebuconazole suppress the development of Black-spotted pond frog embryos at the low concentration as showing teratogenic effects in other assay system. Therefore, teratogen assay system using the Rana nigromaculata embryos could be useful as a tool to evaluate the toxicity of the pollutants in environment.

• Applied Microscopy
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• v.39 no.2
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• pp.107-115
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• 2009

The programed cell death of the cutaneous epithelial tissue during tail regression stages in anuran tadpoles of the blackspotted frog, Rana nigromaculata were visualized by the histochemical and transmission electron microscopic techniques. Metamorphotic changes in the tail regression during the period of the Shumway stage number 31 to 33 are characterized by the disappearance of mucous layer and formation of compound epithelium through cutaneous thickening. Following the TUNEL (terminal deoxynucleotidyl transferase-mediated biotinylated d-uridine triphosphate nick end labeling) staining technique, the apoptotic cells were detected at the distal region of the tail skin initially, but they can be seen at the proximal region according to their following development. It has been also revealed that the number of the TUNEL-positive cells gradually increased from apical to basal direction of the epithelial layers during the tail regressing stages. Following the TEM observation, the early apoptotic cells shown in the epithelium demonstrated condensation and margination of the chromatin material at the nuclear periphery. Another epithelial apoptotic cells were shown nuclear fragmentation, membrane blebbing and cytoplasmic condensation. Following the process of the apoptotic degradation, well preserved organelles and nuclear fragments can be identified in the cytoplasm of lysosome-rich cells, however they soon reduced to lysosomal residual bodies through the progressive degradation.

• The Korean Journal of Zoology
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• v.39 no.3
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• pp.257-265
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• 1996

Previously, we demonstrated that estradiol (E$_2$) was produced by medium sized follicles of Rana nigromaculata and Rana dybowskii in vitro. Present experiments were carried out to determine when the growing follicles have obtained the ability to produce E$_2$. Follicles in different growth stages were isolated and cultured for 6 hours in the presence or absence of frog pituitary homogenates (FPH, 0.1 pituitary/2m1) or various steroid precursors (200 ng/2m1). levels of progesterone (P$_4$), 17 -hydroxyprogesterone (17$\alpha$-OHP), androstenedione (AD), testosterone Cr) or E$_2$ in the medium were measured by RIA. The smallest follicles failed to produce steroids, whereas the smaller follicles produced considerable amounts of steroids (211 pg/follicle), and the medium sized follicles produced a large amounts of steroids (1653 pg/follicle) in response to FPH. Addition of pregnenolone (P5) resulted in a marked increase in P$_4$ but not in other steroids by the smallest follicles whereas the treatment resulted in a marked increase in P$_4$, 17$\alpha$-OHP, AD, T and E$_2$by the smaller and medium follicles. When the amounts of steroids are calculated on the basis of unit surface area (pg/mm$_2$), the ability of the smallest follicles to produce P$_4$ from P5 was similar to those of smaller and medium sized follicles. However, the smallest follicles failed to metabolize P$_4$ to other steroids whereas the smaller and medium follicles did. Taken together, the data suggest that the smallest follicles do not response to FPH in terms of steroid production but they have capacity to convert P5 to P$_4$ and that the smaller follicles have potential to produce E$_2$ although much less efficient than medium sized follicles.

• The Korean Journal of Zoology
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• v.31 no.4
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• pp.251-264
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• 1988

동면 상태에서 혈액성분의 생화학적 변화치를 조사하고자 전남 각지에 서식 또는 광주직할시 근교에서 양식하고 있는 뱀장어, 개구리, 살모사 그리고 다람쥐를 활동기(7월∼8월), 잠입기(10월∼11월), 동진기(12월∼1월) 및 각려기(3월∼4월)에 채집하였다. 이들 동물들의 혈청에서 Total protein, Albumin, Globulin, A/G ratio, Glucose, Calcium, Urea함유량을 조사하여 얻은 성적을 비교 검토하여 다음과 같은 결론을 얻었다. 1 . Total protein의 변화는 각 동물사이에서 상당한 차이를 보이되 잠입기에 다소 증가하였다. 특히 다람쥐에서 Total protein 함유량이 다른 동물들 보다 많았다. Albumin함유량은 잠입기에 상승하였고 동면기에는 약간의 감소를 보이다가 각성기에는 현저한 감소를 보였다. gloulin함유량은 잠입기에 상당히 상승하고 동면기에 약간의 감소를 나타내었으며 각성기 인 봄철에는 많은 증가 현상을 보였다. 2. 혈청 Urea의 함유량은 동면의 각과정에 따라 상당한 차이가 있었다. 즉 잠입기에 약간 상승하고 동면기에는 저하를 보였으며 각성기에는 전 실험동물에서 검출되지 않았다. 3. 혈당의 변화는 잠입기에 대체로 저하하고 동면기에는 심한 저혈당 수준에 이르렀다. 각성기인 봄철에는 다람쥐를 제외하고는 동면기의 혈희량과 유사하였다. 4. 혈청 Calcium함유량의 변화는 활동기에 비하여 잠입기에는 상당한 증가현상을 보였으나동면기에는 전 실험동물이 거의 같은 수준으로 감소를 보이며 각성기에 까지 감소하였다. In order to the biochemical change of the serological components of hibernating animals, eels(hnguillo joponica Temminck et Schlegel), frogs (Rana nigromacurata Hallowell), snakes (Agkistro-don holds breuicaudus Stejneserl, squirrels (Tamias striatus Linnaeus) which were collected around Gwangiu city and the Chunnam area were observed in accordance with the phases of hibernation. The author described the hibernating cycle as active (June-July), prehibematins(October-Novemberl, hibernating (December-January) and posthibemating phase (March-Aprill. The values of total protein, albumin, globulin, hJG ratlo, calcium, glucose and urea were chiefly investigated in their serum. The results are as following: Total protein was shown to be consider-able in eels, frogs, snakes, squirrels and increased in prehibemation. Especially, the mean value was high in sqirrels. Albumin values was increased during prehibemation. But a little decrease was shown during hibernating and an outstanding decrease during posthibemation. The globulin value increased considerably during prehlbemation but decreased a little during hibernation phase. Changes of urea were shown to be considerable according to the stage of each hibem3-tion. A little increase was shown during prehibemation and decrease during hibernating stage. but urea was not found in posthibemation in any experimental animals. The glucose value was generally decreased during prehibematlon. An extremely little increase in glucose was shown during hibernation (hypoglycemia). All hibernating values except those for squirrels in spring posthibemating phase were at almost the same level. The calcium value was shown to be considerable during prehibemation in comparison with active phase. The same level of decrease was represented in all kinds of animals and continued at the stage of posthibemation.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.58-72
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• 1985

A histopathological study was carried out on the duodenum of mice and rats experimentally infected by F. seoulensis. Each mouse was infected with 500 metacercariae and killed after 1, 2, 3 days, 1 and 2 weeks from infection. Each rat was given 1, 000 metacercariae and was examined after 1, 2 and 4 weeks from infection. The duodenal tissue sections of mice and rats were stained with hematoxylin eosin, and PAS stained for the rats of 1 week group. The pathological findings are summarized as below. 1. There were no differences in mucosal findings between the mice and the rats, and between the location of duodenum, 1 and 5 em distal to the pylorus. 2. Each worm embraced a villus exclusively with its foliate fore body which was inserted into the intervillous spaces. The fluke pinched villous epithelia using its oral and ventral suckers. The tribocytic organ destroyed the villous epithelia deeply up to the stroma after 3 days from infection. 3. Apparent villous changes were observed in the mice after 3 days from infection. Villous changes were shortening, widening, blunting or fusion. The villous stroma showed edema, microscopic hemorrhage, capillary congestion, dilatation of lymphatics and inflammatory cell infiltration. The cells were lymphocytes, plasma cells, eosinophils and giant cells. Rarely submucosal and trans:nural inflammation was encountered.

• Korean Journal of Plant Resources
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• v.20 no.2
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• pp.133-144
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• 2007

The vascular plants at the Wolmyung Park was listed 479 taxa: 105 families, 317 genera, 417 species, 1 subspecies, 55 varieties and 6 forms. 479 taxa listed consists of 291 taxa of edible plants (60.8%), 335 taxa of medicinal plants (69.9%), 234 taxa of ornamental plants (48.9%) and 243 taxa of the others (50.7%). Based on the list of the rare plants by the Forest Research Institute, 4 taxa were recorded in the investigated areas; Aristolochia contorta (Preservation priority order, No. 151), Magnolia kobus (No. 187), Prunus yedoensis (No. 110), Berchemia racemesa (No. 67) and based on the list of Korean endemic plants, 9 taxa were recorded; Cephalotaxus koreana, Carex okamotoi, Populus tomentiglandulosa, Prunus yedoensis, Forsythia koreana, Asperula lasiantha, Weigela subsessilis, Adenophora triphylla var. hirsuta, Aster koraiensis. Specific plant species by floral region were total 31 taxa; Prunus yedoensis, Berchemia racemosa in class V, Magnolia kobus, Wistaria floribunda in class IV, 4 taxa (Spiraea salicifolia, Acer palmatum, Asperula lasiantha, etc.) in class III, Caryopteris incana in class II, 22 taxa (Clematis patens, Orixa japonica, Euscaphis japonica, Grewia biloba var. parviflora, etc.) in class I. The naturalized plants in this site were 14 families, 35 genera, 44 species, 2 varieties, 46 taxa and naturalization rate was 9.6% of all 479 taxa vascular plants.

• Korean Journal of Environment and Ecology
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• v.18 no.3
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• pp.333-339
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• 2004

The Frog Embryo Teratogenesis Assay-Xenopus(FETAX) protocol was recently adopted as a valuable tool fur evaluating chemical toxicity and the effect of environmental contaminants in frogs. In this study, the teratogenecity of NiCl$_2$, Carbofuran, Diazinon were determined in the Korean frog, Rana dybowskii using the FETAX protocol. The mortality rate and the percentage of malformed larvae were investigated by probit analysis, The teratogenic concentrations(EC$_{50}$) of NiCl$_2$, Carbofuran and Diazinon were 0.4 and 1.6 and 1.9 mg/1. The embryolethal concentrations(LC$_{50}$) of NiCl$_2$, Carbofuran and Diazinon were 17.6 and 41.5 and 20.2mg/1. The teratogenic indices (TI=LC$_{50}$/EC$_{50}$) were 43.8 for NiCl$_2$, 26.0 for Carbofuran and 10.6 for Diazinon. NiCl$_2$, Carbofuran and Diazinon were shown to be potent teratogens for Rana dybowskii embryo, causing concentration related increase of edema, tail and abdomen. The study results reveal that NiCl$_2$, Carbofuran and Diazinon suppress the development of embryos at relatively low concentrations. Therefore, the Rana dybowskii embryo teratogenesis assay system was proven to be a useful tool to evaluate the toxicity of environmental pollutants.lutants.

• Journal of Plant Biology
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• v.35 no.4
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• pp.403-408
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• 1992

The flowering in Lemna gibba G3, a long-day plant, was promoted under continuous light by agmatine, putrescine, spermidine and spermine present in the culture medium. Methylglyoxal-bis (guanylhydrazone) (MGBG) and cyc10hexylamine (CHA), inhibitors of polyamine biosynthesis, were found to suppress the flowering in the plants. The vegetative grov.1h rate was kept constant while the flowering was being promoted by the pOlyamines, and the inhibitors with depressive effect on flowering showed stimulatory effect on vegetative grov.1h. The pattern of vegetative growth during floral promotion or depression was an indication that the promotive action of the pOlyamines and the suppressive effect of the inhibitors may be outcome of their possible involvement specifically in the flowering process rather than in broad spectrum of growth of L. gibba G3. The degree of promotive action of spermdine and spermine could not be altered (or lessened) by simultaneous application of their inhibitors to the medium. This phenomenon indicates that the flowering process in L. gibba G3 may largely be dependent to the status of endogenous spermidine and spermine. Endogenous level of spermidine in florally induced Lemna, was found to rapidly increase. In 24 h of floral induction, the content reached at the level 2 times higher than that in non-induced plants. The elevated level of spermidine provides an additional, though premature, evidence supporting the postulation that endogenous polyamine status might play an important role in the very early stage of floral induction in L. gibba G3.bba G3.

• Journal of Wetlands Research
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• v.19 no.2
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• pp.193-201
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• 2017

This study was carried out to obtain basic ecological information required for wetland restoration in Korea where wetland is very deficient. To arrive at the objective, we collected the basic ecological information for wetland restoration in four Doombeongs located on Goesan of Chungcheongbuk-do (province), central Korea where maintains relatively integrate feature of Doombeong. Synthesized horizontal distribution of vegetation based on vegetation established naturally except that established by artificial interference, Potamogeton distinctus community, Spirodela polyrhiza community, Sagittaria aginashi community, Trapa japonica community, Scirpus triangulatus community, and Sparganium japonicum community, Persicaria thunbergii community, Juncus effusus var. decipiens community, Ludwigia prostrata community, Humulus japonicus community, Persicaria nodosa community, Miscanthus sacchariflorus community, Phragmites communis - P. japonica community, and Scirpus radicans community, S. gracilistyla community, Spiraea prunifolia for. simpliciflora community, and Rosa multiflora community, and Salix koreensis community and Acer tataricum subsp. ginnala community tended to be established in aquatic zone, herbaceous plant dominated vegetation zone, shrub dominated vegetation zone, and tree and sub-tree dominated vegetation zone, respectively. As the result of DCA ordination based on vegetation data collected from several Doombeongs and their surrounding areas, plant communities tended to be classified into aquatic, wetland, and riparian plant dominated stands. Spatial niche and species composition of major plant communities composing those stands were suggested as the reference information for creating ecological pond as a type of wetland. Further, the importance of wetland and the necessity of wetland restoration was discussed based on functions that the wetland displays.

• Analytical Science and Technology
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• v.15 no.2
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• pp.149-156
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• 2002

In this study, the levels of DEHA, carbaryl, and amitrole contained in the fresh water fishes and amphibians were determined. The 31 sampling sites were selected including 29 sites along the several rivers and 2 sites from the well-known wet lands. The rivers consists of the Han, Nakdong, Kum, Youngsan, and other small scaled rivers. DEHA was detected from 10 sites, but carbaryl and amitrole were not detected at any sites. The highest average concentration of DEHA was determined from the Kum River by $52.7{\mu}g/kg$. In the detected 10 sites, the average concentration of DEHA from fishes was $40.0{\mu}g/kg$, and that from amphibians was $8.90{\mu}g/kg$ which indicates that 5 times more DEHA was observed from fishes than amphibians. The detection frequency from fishes was 10/62 while that from amphibians was 2/62, and the highest concentration from fishes was $95.5{\mu}g/kg$ (crucians from Kongjoo) and that from amphibians was $12.1{\mu}g/kg$ (bullfrog from Najoo). Among the 10 detected sites, 6 sites were agricultural area and the other 4 sites were semi-urban area.