• The Korean Journal of Zoology
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• v.31 no.3
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• pp.177-184
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• 1988

The pattern of progesterone production and secretion of frog(R. dybowskii) follicles was investigated in follicle culture in vitro. Involvement of cAMP in the regulation of the steroid production by the follicles was also investigated by manipulating endogeneous cAMP level with forskolin and/or 3-isoburyl- 1 - methylxanthine(IBMX). Endogeneous follicular progesterone level increased rapidly in one hour of culture by treatment of frog pituitary homogenate(FPH) and reached peak level at 2 hours or later. But the absolute amount of progesterone produced (60-300 pg/follicle) or the peak time of the honnone level was different between individual animals. Basal level of progesterone in untreated sister follicles was very low (around 10 pg/follicle) and nearly undetectable in most cases regardless of culture lime. Secretion level of progesterone by the follicles obtained by measunng the honnone in the culture media was just the reflection of the intrafollicular level. Exogeneously added forskolin, an adenylate cyclase stimulator, and/or IBMX, a phosphodiesterase inhibitor, could mimic FPH action in terms of progesterone production and secretion. Thus, it seems clear that FPH regulates progesterone production via cAMP system in the follicle cells.

• The Korean Journal of Zoology
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• v.33 no.2
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• pp.175-182
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• 1990

Progesterone production and oocyte maturation in ovarian follicles of Rana nigromaculata and Rana rugosa were investigated. Addition of frog pituitary homogenate (FPH) to the in utiro cultured follicles of R. nigromaculata stimulated a marked increase in the accumulation and secretion of progesterone (P$_4$) by the follicles and induced their oocyte maturation (germinal vesicle breakdown, GVBD) in a dose dependent manner. The FPH (0.1 pituitary equivalent/2 ml)-inducted P4 peak appeared in 3-6 hours and followed by the oocyte GVBD in 9-12 hours after the hormone stimulation. lncreae of intrafollicular cAMP levels with forskolin (an adenylatecyclase stimulator) and 3-isobutyl-1-methylxanthine (IBMX, a phosphodiesterase inhibitor) mimic the FPH action in the stimulation of P$_4$ production but not in the induction of oocyte maturation. The in uitro cultured follicies of R. rugosa behaved very differently from other amphibian follicles. Addition of FPH-(0. 1 pit. equivl2 ml) to the culture medium neither stimulated P$_4$ production by the follicles nor induced the oocyte GVBD. However, treatment of the follicles with forskolin and IBMX drastically stimulated both the intrafollicular accumulation (800 pg/follicle) and secretion (1700 pg/follicle) of P$_4$ by the follicles during culture period. Thus, the data suggest that the follicles are ready to respond to cAMP increase but not to the FPH stimulation in terms of P$_4$ production.

• The Korean Journal of Zoology
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• v.24 no.3
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• pp.133-144
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• 1981

The ultrastructures of the pigment cells in the Asiatic land salamander (Hynobius leechi) dorsal skin were obtained by means of electron microscope. The results were as follows; 1. The pigment cells of the epidermis consisted of the melanocytes in the germinal layer and of the melanophores distributing to the keratinocyte layer. The traits of these cells in the epidermis were as follows: A. The nuclei of the melanocytes were round or oval in shape and appeared as partly small or large infoldings of the nuclear envelope. B. Rough-surfaced endoplasmic reticulums and Golgi complexes were well developed in infranuclear cytoplasm. Many ribosomes were mainly distributed around the perinuclear portion. C. The melanosomes of the melanocytes were observed as a found or an oval shape and strong electron-dense or less electron-dense melanosomes were observed. D. The infoldings of the nuclear envelope in the melanophore were partly found deeper than those of the melanocyte. The cytoplasm of the melanophore filled with melanosomes caused organelles not to be observed in that. 2. The pigment cells in the dermis were composed of the xanthophores just beneath basement membrane and the melanophores in the connective tissue. The traits of these cells in the dermis were as follows: A. The xanthophores contained round or oval vesicles, and these vesicles were divided into 6 types (type I pterinosome, type II pterinosome, type III pterinosomes, type iv pterinosome, type V pterinosome, type VI pterinosome). B. Most of the nuclei of the melanophores in the dermis were elongate in shape, and a portion of the nuclear envelope was deep infolded. C. Becuase the cytoplasm was filled with the melanosomes of the same electron-density, organelles were not observed in the cytoplasm. D. Two processes of the melanophore in the dermis extended in parallel with a xanthophore and the cytoplasm in those processes were filled with the melanosomes.

• The Korean Journal of Zoology
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• v.21 no.1
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• pp.29-39
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• 1978

The authors observed the ultrastructure of the mucous glandular epithelial cells in the amphibian skin by mean of electron microscope. The specimens from the experimental animals were fixed in 2.5% glutaraldehyde-oaraformaldehyde fixative in phosphate buffer at pH 7.2 prior to fixation in 1% osmium tetroxide, dehydrated in graded ethanol and acetone, embedded in Epon 812 mixture, and sectioned with Sorvall MT-2 ultramicrotome. The ultrasections were contrasted with uranyl acetate and lead citrate and observed with a JEOL-100B electron microscope. The results were as follows: 1. The cutaneous mucous glands in amphibia consisted of the glandular epithelial and the myoepithelial cells. 2. Several different cells in ultrastructure were observed in the mucous glandular epithelium of the adult amphibian skin. a. The dark and the light cells were observed in Hynobius leechi. b. The mitochondria-rich and the round secretory granule-containing cells were observed in Bombina orientalis. c. The round secretory granule-containing and the foam-like granule mass-containing cells were observed in Kaloula tornieri. d. The cutaneous mucous gland of Rana nigromaculata were divided into two types: A and B-type glands. In the A-type mucous gland, the mitochondria-rich and the round secretory granule-containing cells and in the B-type mucous gland, the mitochondria-rich, the secretory granule-containing and the ER-rich cells were observed. 3. Based upon the above findings, the authors infer that the mucous granular epithelium of the amphibian skin consists of the mitochondria-rich undifferentiated, the secetory granule-containing and mature, and the ER-rich evacuated cells.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.299-312
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• 2023

The paddy environment is classified as a wetland and occupies a very large proportion of the freshwater environment. It is also ecologically important as a habitat and spawning ground for many aquatic insects and amphibian larvae. However, due to climate change and indiscriminate spraying of pesticides, the rice field ecosystem is continuously threatened. In order to restore ecologically damaged rice paddies in the future, information on organisms living in the rice paddy ecosystem, which can serve as a restoration standard, is needed. The eDNA metabarcoding analysis method is a very effective means of accumulating information on many organisms living in the rice field ecosystem because it can indirectly identify the existence of taxa that are no longer found in the target ecosystem due to different adult life periods or metamorphosis. In this study, genes of four species of frogs and nine species of aquatic insects were also discovered, and some taxa were directly discovered in the field. A large number of taxa have been discovered only by DNA searches, and traditional survey methods have only been able to identify very limited taxa. This eDNA-based paddy field biosearch is expected to be very useful in the investigation of biodiversity in agricultural ecosystems due to its strong analytical resolution.

• Journal of Wetlands Research
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• v.6 no.3
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• pp.107-118
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• 2004

The flora of the vascular hydrophytes and hygrophytes and the change of flora according to the fluctuation of the water level before and after flooding were investigated from September 2002 to October 2003 in Woopo Wetland and Topyeong Stream, Changnyeong-gun, Gyeongsangnam-do, Korea. The flora of the Woopo, Mokpo, Sajipo, Jokjibyeol, Topyeongcheon Upstream, and Topyeongcheon Downstream were composed of 256, 242, 265, 177, 201, and 180 taxa, respectively. The flora of total study area was 86 families, 232 genera, 302 species, 42 varieties, 6 form, or total 350 taxa. Among them, hydrophytes, hygrophytes, and others were 36, 96, and 218 taxa, respectively. The life form of the vascular hydrophytes was classified as 19 taxa of emergent plants, 6 taxa of floating-leaved plants, 4 taxa of free-floating plants, and 7 taxa of submersed plants. The specified wild plants designated by the Korean Association for Conservation of Nature, Ministry of Forest, and Ministry of Environment were Euryale ferox, Hydrocharis dubia, Persicaria amphibia, Acorus calamus var. angustatus. And Aristolochia contorta was distributed in the study area. The floras of the naturalized plants of the Woopo, Mokpo, Sajipo, Jokjibyeol, Topyeongcheon Upstream, and Topyeongcheon Downstream were composed of 27, 25, 35, 21, 26 and 24 taxa, respectively. The flora of the naturalized plants of total study area was 43 taxa, this equalled 12.3% of total vascular plants in the study area. And 165~244 taxa were surveyed in the each study area before flooding, total 299 taxa, and 86~212 taxa after flooding, total 299 taxa. Among them, hydrophytes, hygrophytes, and others were 33 and 29, 93 and 83, 183 and 187 taxa before and after flooding, respectively. Before and after flooding, the species number of emergent plants, floating-leaved plants, free-floating plants, and submersed plants was nearly the same. It was guessed that vascular hydrophytes and hygrophytes adapted to fluctuation of the water level in the study area.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.239-251
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• 2011

To compare the different water environments in the Jigsaw stream (st. 1, 2) and Jujin stream (st. 3, 4) crossing over the Byeonsan-Bando and Seonunsan parklands, the physico-chemical factors and the species compositions of epilithic diatoms were analyzed from March 2009 to February 2010. The mean values of conductivity (681.1 ${\mu}S\;cm^{-1}$), suspended solids (27.83 mg $L^{-1}$), biological oxygen demand (3.15 mg $L^{-1}$), total nitrogen (3.24 mg $L^{-1}$), total phosphorus (0.24 mg $L^{-1}$) and chlorophyll-${\alpha}$ (12.99 mg $m^{-3}$ ) in Jujin stream were significantly higher than each element in Jigsaw stream. Eighty taxa were classified into 73 species and seven varieties belonging to 24 genera, eight families, three suborders and two orders in Jigsaw stream. Eighty eight taxa were classified into 81 species and seven varieties belonging to 22 genera, seven families, three suborders and two orders in Jujin stream. Biological water quality assessments revealed that Jigsaw stream was ${\beta}$~${\alpha}$-oligosaprobic and Jujin stream was ${\beta}$-mesosaprobic. Dominant and diversity indices were indicated from 0.25~0.81 and from 1.73~4.14 in Jigsaw stream, respectively, and from 0.29~0.64 and from 2.72~4.02 in Jujin stream, respectively. Jujin stream was more eutrophic than those of Jigsaw stream. The different water environments between the two streams could be due to the different ecosystems of the neighboring basins of each stream crossing over in the mountain. Further studies should investigate the water environments of two streams by continuous and regular monitoring to analyze the different ecosystem mechanisms.

• Applied Microscopy
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• v.15 no.2
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• pp.31-68
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• 1985

Authors are trying to unveil the ultrastructural organization of olfactory bulb, which has been summerized under light microscopic level or communicated only in some detail in different view point until now. For the critical point of view, since the phylogenetical approach will give the ultimate value in the correlative study between structural and functional bases (Brodal, 1969), the present study was carried out light and electron microscopic analyses of the structures of the neurons and synaptic organizations in olfactory bulbs from different animals in phylogenetical scale. We selected each one species from five animal classes: the house rabbit(Oryctolagus cuniculus var. domesticus [Gmelin]) from Mammalia, the domestic fowl (Gallus gallus domesticus Brisson) from Aves, the viper (Agkistrodon hylys [G.P. Pallas]) from Reptilia, a frog (Bombiana orientalis Boulenger) from Amphibia and the crussian carp (Carassius carassius [Linne]) from Pisces. For light microscopic study, samples were fixed in 10% formalin and paraffin sections were stained with hematoxylin-eosin. For the electron microscopic study, the tissues were fixed by perfusion through the heart or immersion with 1% paraform-aldehyde-glutaraldehyde mixture (phosphate buffer, pH 7.4), and final tissue block trimmed under dissecting microscope were osmicated (1% OsO4), they were embedded in Araldite or Epon 812, and ultrathin sections were made by LKB-V ultratome following the inspection of semi-thin sections stained with toluidine blue-borax solution. Ultra-thin sections contrasted with uranyl acetate and lead citrate were observed with JEM 100CX electron microscope. We have summerized our morphological analyses as follows: 1. The olfactory bulb of rabbit, viper and frog shows the eight layers of fila olfactoria, glomerular, external granular, external plexiform, mitral cell, internal plexiform, internal granular, medullary but domestic fowl shows the five layers of glomerular, fibrillar, mitral, granular and medullary and the three layers of fibrilla, glomerular and medullary in crussian carp. The sharpness of demarcation between the layers shows deferential tendency according to phylogenetical order. 2. Mitral cells of vertebrate have large triangular or oval shape with spherical nuclei which contain not so much chromatin. The cytoplasm contains numerous cell organelles, of which Nissl's bodies or granular endoplasmic reticula arranged as parallel strands. Development of granular endoplasmic reticula were declined as the phylogentical grade is going lower. 3. Tufted cells of all animal are mostly spindle or polygonal contour and contain oval nuclei which located in periphery of cytoplasm. The nuclei of rabbit, fowl, viper and frog has relatively space chromatin, but a nucleus of crussian carp contain irregularly aggregated chromatin in karyoplasm. Their cytoplasmic volume and cell organelle contents are in between those of mitral cell and granular cell. They contain moderate amount of mitochondria, granular endoplasmic reticula, a few Golgi complex, polysomes, lysosome, etc. 4. Granule of cells of all the vertebrate amimals studied exhibit similar features; cells and their dense nuclei show spherical or oval contour, and they have the thin rim of cytoplasm which contain only a few cell organelles. 5. In rabbit, the soma of mitral cells were in contact with boutons with two types of synaptic vesicles, that is, round and flat vesicles, especially flat vesicles in boutons were showing reciprocal synapses. However, in domestic fowls, vipers, frogs and crussian carps, there were found boutons showing only spherical synaptic vesicles. 6. The boutons containing round synaptic vesicles were made contact with the some of tufted cell of olfactory bulb in the rabbits, fowls, vipers and frogs, but no synaptic boutons were observed in soma of tufted cells in crussian carps. In the frogs, there were observed dendrites were contact with the soma of tufted cells. 7. In the neuropils of plexiform, granular and glomerular layers olfactory bulbs in the vertebrate, the synapses were axo-large dendrites, axo-median and small dendrites, dendrodendritic, and axo-axonal contacts. However, in the neuropil of crussian carps, synapses were observed only in glomerular layer.

• Journal of Environmental Impact Assessment
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• v.31 no.1
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• pp.11-46
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• 2022

This study was carried out to examine vascular plants and invasive alien plants in Gyodong Island, located at the northwestern Civilian Control Line (CCL) of Ganghwa-gun, Incheon, and to use them as basic data for systematic management of identified plants and establishing biodiversity conservation measures. The survey was conducted 13 times from April 2019 to August 2021. The vascularflora in Gyodong Island was identified as 109 families, 378 genera, 641 species, 15 subspecies, 49 variants, 8 forma, a total of 713 taxa. This was found to be about 15.36% of the total 4,641 taxa of vascular plants in Korea. The northern linage plants on the Korean Peninsula appearing in the Gyodong Island area were identified in 83 classification groups, including Red-based leaf edge (Carex erythrobasis H.Lev. & Vaniot). Korea endemic plants were identified as 16 taxa such as Seoul wild-ginger [Asarum heterotropoides var. seoulense (Nakai) Kitag.], and a total of 20 taxa of rare plants designated by IUCN were observed, including the endangered grade Beardless iris (Iris ruthenica Ker Gawl.). Floristic target species were classified with a total of 99 taxa. For V grade, Beardless iris 1 taxon was found. and also IV grade and III grade were identified in 8 taxa and 20 taxa respectively. The invasive alien plants identified as 75 taxa, such as Verbesina alternifolia (L.) Britton ex Kearney. The naturalization rate was 10.51%, and the urbanization index was calculated as 23.29%. Since large-scale construction has been currently underway on Hwagae Mt. in Gyodong Island as the target of survey area, the influx of invasive plants will be expected to promote. Therefore, it is urgent to establish in-situ protection and conservation measures for notable plants such as Beardless iris and Water smartweed [Persicaria amphibia (L.) S.F.Gray].