• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.1-10
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• 2007

The persistent and ubiquitous environmental contaminant, tributyltin chloride (TBT), induces not only imposex in gastropods but also the differentiation of adipocytes in vitro and increases adipose mass in vivo in vertebrates. TBT is a nanomolar affinity ligand for retinoid X receptor (RXR) in the rock shell(Thais clavigera) and for both the RXR and the peroxisome proliferator activated receptor $\gamma(PPAR\gamma)$ in the amphibian (Xenopus laevis), mouse, and human. The molecular mechanisms underlying induction of imposex by TBT have not been clarified, though several hypotheses are proposed. TBT promotes adipogenesis in the murine 3T3-L1 cell model and perturbs key regulators of adipogenesis and lipogenic pathways in vivo primarily through activation of RXR and $PPAR\gamma$. Moreover, in utero exposure to TBT leads to strikingly elevated lipid accumulation in adipose depots, liver, and testis of neonate mice and results in increased adipose mass in adults. In X. laevis, ectopic adipocytes form in and around gonadal tissues following organotin, RXR or $PPAR\gamma$ ligand exposure. TBT represents the first example of an environmental endocrine disrupter that promotes adverse effects from gastropods to mammals.

• Animal cells and systems
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• v.6 no.1
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• pp.69-74
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• 2002

Recent evidence has suggested that trunk neural crest cell generally assumed to have equivalent differentiation potentials, demonstrate differentiation bias along the anterior/posterior axis. In amphibian and fish, neural crest cells give rise to three chromatophore types, melanophores, xantho-phores, and iridophores. Each pigment cell type has distinct characteristics but there is speculation about the cellular plasticity that exists among them. Neural crest cells migrate along specific routes, ventromedially and dorsolaterally. Neural crest cells that travel dorsolaterally are the first cells to begin migration in the axolotl and are the major contributors to the visible pigment pattern. Many factors and mechanisms that are responsible for guiding migratory neural crest cells along potential pathways or determining their fate remain unknown. A single lineage of the crest, which becomes restricted to one of the three pigment cell types, gives us the opportunity to examine the existence of neural crest stem cell populations and cellular plasticity. Study presented here showed results from recent in vitro studies designed to identify parameters influencing differentiation events of individual neural crest-derived pigment cell lineages. Melanophore production from neural crest explants originating from different levels along the anterior/posterior axis of wild type-axolotl embryos were compared and demonstrate that the differentiation of melanophores is enhanced in subpopulation of neural crest treated with forskolin. Forskolin (an adenylate cyclase activator) increases intracellular CAMP concentration and eventually activates the protein kinase-A signaling pathway. Melanophore number, melanin content, and tyrosinase activity in explants taken from the anterior-most region of the crest increased significantly in response to forskolin treatment. This study suggests implications of region specific influences and developmental regulation in the development of pigment pattern.

• Pediatric Infection and Vaccine
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• v.20 no.1
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• pp.41-45
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• 2013

Nontyphoidal Salmonella are gram negative bacilli organism, which may induce systemic infection such as febrile enteritis, bacteremia, and osteomyelitis. Main route of infection is known as food but also possible through reptile, amphibian, and fish raised as pets in the house. There is no known cases report of Salmonella infection through pets in Korea and also rare in the overseas. We report 2 patients who visited Severance children's hospital with chief complaint of fever and diagnosed as nontyphoidal salmonellosis. Each case had a history of raising turtle or tropical fish with possibility of Salmonella infection through these pets. Increasing incidence of raising pet reptile and fish lately, contact precaution and proper prevention and control of Salmonella infection of these pets especially in children under 5 years old are necessary due to higher risk of serious complications of salmonellosis.

• Korean Journal of Environmental Biology
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• v.29 no.1
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• pp.1-10
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• 2011

Amphibian population declines globally. Aquatic contamination by organic pollutants including endocrine disrupters has been suspected to the one of the reason for distinction of amphibia which has obligate aquatic life style during larval period. Amphibians have been widely accepted as animal model for the study of endocrine disruption in aquatic ecosystem at molecular as well as individual levels. There are increasing need for toxicological data in amphibians at multiple endpoints for management of contamination and development of safety guideline for important EDs in aquatic media. Alkylphenols have been widely used in agricultural, industrial, and housekeeping activities, contaminating the aquatic media and evoking endocrine disruption in aquatic animals. In this review, we summarized data concerning the endocrine disruption by alkylphenol organic pollutants on amphibians according to route, concentration, terms, and developmental stage of exposure together with mechanism of endocrine disruption.

• Korean Journal of Environment and Ecology
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• v.18 no.2
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• pp.205-209
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• 2004

For the purpose of this study was accumulating histological data of skin some amphibia near Chiri Mt. and Moodeung Mt. Analyzed Anura and Caudata were Rana nigromaculata, Rana rugosa, Rana catesbeiana, Hynobius leechii. The histological prepared skin of frogs were compared, of which were selected from dorsal and belly. Excretory glands were identified granular glands, mucous glands, serous glands, vacuoles and excretory ducts in epidermal and dermal tissue. And developing excretory glands, well developed excretory glands and post developing excretory glands were identified also. These results were significantly as basal data on the comparative epidermal skin histology on some Korean Amphibia. Probably these glands of amphibian skin could be infered which were adaptable structure to ecological suffered condition. Following study of these results were more considerable data for comparative histology, comparative anatomy and comparative physiology and ecology of Amphibia.

• Korean Journal of Environment and Ecology
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• v.20 no.4
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• pp.400-406
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• 2006

To investigate the incidence of the road-kill of amphibians and reptiles in Songgye valley, Woraksan National Park, a survey of Songgye valley was conducted from January, 2003 to December, 2005. Before the investigation, the survey area was divided into 50 sites at 300m intervals. As a result, road-kill by vehicles were confirmed to affect 40% of the amphibians and 68.3% of the reptiles among the total species in the Woraksan National Park. The most affected species was Rana dybowskii, with a frequency of 94.9% among the total number of road-killed Individuals. The highest road-kill rate occurred between April to May, every year. Therefore, it is necessary to construct an eco-bridge and to perform the continuous ecological monitoring for the conservation of R. dybowskii including other species.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.32-43
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• 2004

Targeting a rooftop biotope created in urban area, this study aims at verifying a creation technique reflecting an urban biosphere reserve concept as well as its function as the habitats of various wild animals. To this end, a set of processes of a biosphere reserve-based basic conception and master plan, sectoral plans, construction and monitoring were applied to the rooftop of 12-story UNESCO Building in Seoul. In particular, the rooftop habitats were divided into core area, buffer zone and transition area, and habitats and facilities suitable to the characteristics of each space were planned. By aligning a plantation planning map with environmental conditions such as topography and water, creation of diverse habitats was enabled. As a result, a set of various habitats including wetlands, wild grassland, shrubs, forest trees and vegetable fields was created at the site. Species living in these habitats included 148 plant species, 62 insect species, 2 amphibian species, 3 fishery species and 3 bird species. The rooftop eco-park of UNESCO Building, which was created one year ago, is assessed as an important space for conservation of biodiversity as well as a place where a biosphere reserve concept was well applied. Meanwhile, for this rooftop biotope to be a pioneer of urban biosphere reserve-based types, a number of principles & methodologies suggested in this study need to be applied, In a perspective of landscape ecology, maintenance efforts should be linked with green areas in neighboring areas, which are the sources of species, In addition, considering that the rooftop biotope is a restored ecosystem, theories and approaches from restoration ecology should be applied. On-going monitoring on environmental changes is also required as the site is located in the urban center, Ultimately, rooftop biotopes including the case study area should contribute in promoting the socio-economic, cultural, and spiritual sustainability as well as environmental sustainability of a city.

• Development and Reproduction
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• v.21 no.4
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• pp.425-434
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• 2017

Polyploidy is occurred by the process of endomitosis or cell fusion and usually represent terminally differentiated stage. Their effects on the developmental process were mainly investigated in the amphibian and fishes, and only observed in some rodents as mammalian model. Recently, we have established tetraploidy somatic cell nuclear transfer-derived human embryonic stem cells (SCNT-hESCs) and examined whether it could be available as a research model for the polyploidy cells existed in the human tissues. Two tetraploid hESC lines were artificially acquired by reintroduction of remained 1st polar body during the establishment of SCNT-hESC using MII oocytes obtained from female donors and dermal fibroblasts (DFB) from a 35-year-old adult male. These tetraploid SCNT-hESC lines (CHA-NT1 and CHA-NT3) were identified by the cytogenetic genotyping (91, XXXY,-6, t[2:6] / 92,XXXY,-12,+20) and have shown of indefinite proliferation, but slow speed when compared to euploid SCNT-hESCs. Using the eight Short Tendem Repeat (STR) markers, it was confirmed that both CHA-NT1 and CHA-NT3 lines contain both nuclear and oocyte donor genotypes. These hESCs expressed pluripotency markers and their embryoid bodies (EB) also expressed markers of the three embryonic germ layers and formed teratoma after transplantation into immune deficient mice. This study showed that tetraploidy does not affect the activities of proliferation and differentiation in SCNT-hESC. Therefore, tetraploid hESC lines established after SCNT procedure could be differentiated into various types of cells and could be an useful model for the study of the polyploidy cells in the tissues.

• International Journal of Oral Biology
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• v.49 no.2
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• pp.48-52
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• 2024

This study explores the histological features and Bmp4 expression patterns in the replaced tooth germ of Xenopus laevis. Tooth germ formation starts from the dental placode through epithelial-mesenchymal interactions, involving various signaling pathways such as Fgf, Shh, Bmp, and Wnt. In mice, Bmp4 expression in the dental placode inhibits Pax9 expression in the dental mesenchyme. Although absent in the presumptive dental lamina of birds and toothless mammals, Bmp4 remains conserved in reptiles and fish owing to gene duplication. However, its expression in amphibian tooth germs is poorly understood. Three-month-old X. laevis were employed in this study. Initially, samples underwent paraffin embedding and were sectioned into 5 or 12 ㎛ ribbons for H&E staining and in situ hybridization, respectively. Results revealed teeth appearing in two maxillary rows: the labial side, with prefunctional and functional teeth, and the lingual side, with replaced tooth germs behind functional teeth. Enameloid was observed between the inner dental epithelium and dental mesenchyme at the cap or early bell stages, whereas enamel and dentin formed during the late bell or mineralization stages from the replaced tooth germ. Bmp4 expression was evident in the inner dental epithelium (ameloblasts), dental papilla (odontoblasts), stellate reticulum, and Hertwig's epithelial root sheath. Overall, these findings highlight the conservation of Bmp4 expression in X. laevis tooth development.

• Journal of Wetlands Research
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• v.22 no.1
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• pp.8-14
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• 2020

This study was carried out to compare the Snout-vent length (SVL) and the biomass for the endangered species II, narrow-mouthed toad (Kaloula borealis), at the three different latitude sites (Seoul, Nonsan, Busan) in Korea. For the narrow-mouthed toad study, pitfall traps and inducement traps were used to catch the species, and environmental factors (temperature, precipitation, humidity) were compared by region. As a result of this study, each of the male narrow-mouthed toads' SVL and biomass in Busan was 41.6±0.39mm, and 11.3±0.17g, which showed that it was the biggest and heaviest among the three regions. For Seoul and Nonsan, each of the SVL of the female narrow-mouthed toad was 36.6±2.03mm, 36.6±1.76mm, and the biomass was 8.1±0.55g, 8.2±0.91g, which showed that there was no significant difference between Seoul and Nonsan. Each of the female narrow-mouthed frogs' SVL and biomass in Busan was 44.7±0.35mm, 13.1±0.18g, which was also biggest but showed no significant difference in biomass by region. Concluding, this showed that the female narrow-mouthed toad in Busan is larger and heavier than those of other regions. We hope this study will be a standard for the future amphibian research with comparing the SVL and biomass for the endangered species II, narrow-mouthed toad. It is expected that if this kind of study keeps for long, it will be a basis for understanding changes in biomass of amphibian species due to climate change.