• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.207-212
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• 1994

The census of Amphibia fauna in Tokyusan National Park was carried out during April 10, 1993 and August 8 - August 9, 1993 at the areas of construction field of golf course in Muju Resort and the Chibong. There were 6 species of 5 genera on the 4 families, 2 orders of Amphibia in Tokyusan National Park including Hynobius leechii. Onychodactylus fischeri, and Bufo bufo gargarizans which were announced the specific wild animals with the object of conserving by The Ministry of Environment. At the area of construction field of golf course in Muju Resort, there were 5 species of Amphibia observed as Hynobius leechii, Bombina orientalis, Bufo bufo gargarizans, Rana nigromaculata, and Rana dybowskii. Onychodactylus fischeri and Rana dyhowskii were observed at the Chibong area. The Chibong inwhich was observed 9 relatively large number of individuals of Onychodactylus fischeri was revealed as an environmentally sound habitat to Onychodactylus fischeri. Whereas in the construction field of golf course, there were intended to diminishing species and population size rapidly by progress with construction works. Therefore the large construction works such as golf couse and ski slopes which were concerning to deteriorate the natural environment should be restrain in National Park for animal diversity conservative.

• The Korean Journal of Zoology
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• v.39 no.3
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• pp.273-281
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• 1996

Previously, we have proposed a two-cell type model for follicular steroidogenesis inamphibians with Rana nigromacu lota. Present experiments were carried out to ascertain whether the model Is applicable to R. dybowskii. The role of theca layer were also reassessed by using granulosa cell-free pure theca layer (P-THEP). Theca/epithelium (THEP) layers, P-THEP layers, and granulosa cell enclosed-oocytes () were obtained from ovarian follicles of R. dybowskii by microdissection. Intact follicles (IFs) and different types of tissues were cultured for 6 hour in amphibian Ringer's m the presence or absence of FPII (0.05 gland/mi) or various steroid precursor (100 ng/ml). The amounts of product steroids converted by the components were measured by RIA. Exogenously added pregnenolone (P5) resulted in a marked increase in progesterone (P$_4$) by GCEOs (2143 pg/follicle) and IFs (2346 pg/follicle) but a smaller increase in P4 by THEP layer (495 pg/follicle). Addition of P$_4$ increased 17 a-hydroxyprogesterone (17 $\alpha$-OHP$_4$) levels by GCEOs (1118 pg/follicle) and IFs (1333 pg/follicle) but less by THEP layer (290 pg/follicle). However, much less amounts of P$_4$ or 17 $\alpha$-OHP$_4$ were producad by P-THEP layers than THEP in the presence of P5. Exogenous 1 7$\alpha$-OIIP$_4$ increased androstenedione (AD) levels by GCEOs (1415 pg/follicle) and IFs (561 pg/follicle) but not by THEP layers. In contrast, addition of AD resulted m a marked increase in testosterone (T) levels by TIIEP (2594 pg/follicle) and IFs (2223 pg/follide) but much less by GCEOs (339 pg/follicle). Exogenous T increased estradiol (E$_2$) levels by GCEOs (551pg/follicle) and IFs (887 pg/follicle), but not by THEP layer (<10 pg/follicle). Without addition of FPH or steroid precursors, very low or nondetectable levels of steroids were produced (< 20 pg/follicle) by all the types of follicular components examined. The data presented here indicate that the two-cell type model based on the study with R. nigromacu Iota is applicable to R. dybowskii and also suggest that the minor pathway, which convert P5 to 17$\alpha$-OHP$_4$, is not present in theca layer.

• The Korean Journal of Zoology
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• v.24 no.1
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• pp.38-57
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• 1981

Cardell, Jr. (1964)는 도룡뇽의 뇌하수체 전염에서 5가지의 분비세포를 구분하였으며 Dent와 Gupta (1967), 그리고 Iturrza (1964)는 영원류에서 5가지 분비세포를 구분하여 보고한 바 있다. 또 Doerr-Schott (1965)는 개구리에서 5가지 분비세포를, Mira-Moser (1969, 1970)는 6가지의 분비세포와 한가지의 무과립세포를 구분하였다. Shinkawa등 (1972)도 역시 7가지 cell type을 구분하였다. Shinkawa와 Nakai (1972)는 참개구리에서 역시 7가지 cell type을, 그리고 이들이 선정한 3 cell type에서 ACTH를 분비한다는 사실을 보고 하였다. 이에 본 연구자들은 산개구리를 재료로 하여 우선 동면기의 것을 실험하였던 바 7가지 cell type을 구분한 바 있고, 다시 활동기의 것을 재료로하여 세포내 소기관의 변화를 관찰하였는데 여기서 몇가지 차이점을 보고하는 바이다.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.425-432
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• 2006

The tadpoles of 12 Korean anuran species, including Bombina orientalis, Bufo gargarizans, B. stejnegeri, Hyla japonica, Kaloula borealis, Rana dybowskii, R. huanrenensis, R. coreana, R. nigromaculata, R. chosenica, R. rugosa, and R. catesbeiana, were classified based on their morphological characteristics. We collected eggs or tadpoles of the 12 Korean anuran species from Gangwon, Incheon, Chungcheong, and Gyeonggi districts in 2005 and 2006 breeding seasons. When the tadpoles reached at $27{\sim}37$ Gosner's developmental stages, we described morphological characteristics of the tadpoles of each anuran species and measured their physical parameters such as total length, body length, and body mass. After that, we chose 12 morphological characteristics to identify each species and to use them as classification keys such as eye location, caudal musculature pattern, spiracle location, oral disc morphology, and labial tooth row formula. In this paper, we presented classification keys, morphological characteristics, and drawings for the tadpoles of 12 anuran species.

• Korean Journal of Environment and Ecology
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• v.11 no.4
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• pp.391-396
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• 1998

Herpetofauna of the Naesorak in Sorasan National Park was carried out both June 30, 1997~July 3, 1997. 6 species of 5 Families in Amphibian and 3 species of 3 families in Reptilian were observed in thes survey. It was observed relatively poor biota to Kaya, Sokri, and Chri National Park in Korea. There were three Specific Endangered Animal assigned by Minister of Environment such as Bufo stejnegeri, Rana dybowskii and Eremius argus. Especially Eremius argus was abundantly distributed around Limansuryonjang. So Limkansuryonjang should be conserve for Eremias argus's stable environmental condition.

• Korean Journal of Environment and Ecology
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• v.20 no.3
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• pp.345-351
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• 2006

This study investigates the toxic effects of $Cd^{2+}$on frog (Rana dybowskii) by the determination of oocyte maturation and development of embryo exposure to different concentrations of the toxicant. The results show that $Cd^{2+}$ concentration of 0.1ppm suppressed the maturation of the oocytes. To examine the reversibility of the inhibitory effects, the oocytes were exposed to the $Cd^{2+}$ only for 3 hours, and then transferred to plain medium and cultured further for 17 hours. The oocytes were recovered from the toxic effect of the $Cd^{2+}$ when they were exposed to 1ppm, but not to 2.5ppm of the $Cd^{2+}$. The development of 2 cell embryos to 32 cell was completely suppressed at 0.1ppm and the longer the embryos were exposed to the $Cd^{2+}$, the more damage appeared to the embryos and the cytolysis of the 32 cell was induced by $Cd^{2+}$ at 0.1ppm. On the other hand, the embryos of blastula stage were cultured 96 hours in presence of the $Cd^{2+}$ at various concentrations and were examined. The rates of mortality and malformed larvae were investigated by probit analysis. From the results of LC$_{50}$ of 0.1ppm and EC$_{50}$ of 0.08ppm, Tl of 5.0 was derived, which indicates $Cd^{2+}$ is to be considered a teratogenic compound. Such specific malformations occurred in 14.3% as spine deformations at the 0.05ppm, in 75.0% as tail deformations at the 0.1ppm, in 66.7% as abdominal deformations at the 0.01ppm and in 26.0% as profound deformations at the 0.1ppm of $Cd^{2+}$ concentration which living embryos were exposed to. $Cd^{2+}$ suppressed growth to head-tail length at 0.1ppm. In conclusion, The study results reveal that $Cd^{2+}$ must be considered highly toxic effect to oocyte maturation and embryonic development.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.273-280
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• 2014

This study examined whether Dybowski's brown frogs(Rana dybowskii) in noisy highway roadsides had different mating calls from those in natural sites. We selected four study sites: two rice paddy sites in Youngdong Highway roadside and two nearby natural counterparts. Frog calls were recorded between 18:30 and 20:00 on February 24, February 27, and March 14, 2014. Frog calls in the natural sites had fundamental frequency approximately at 700 Hz with two to four apparent harmonics, while frog calls in the highway sites had higher fundamental frequency with up to seven apparent harmonics. Analysis of variance (ANOVA) shows that a roadside site that are directly exposed to highway noise had statistically higher frog calling frequency than other study sites. However, the higher calling frequency was not found in another roadside site that differed in elevation from the highway and was buffered by forests. These results indicate that male frogs in a noisy highway roadside called females with a higher pitch and more apparent harmonics to avoid being masked by highway noise. These results also suggest that there is a threshold noise level that interrupts frog's mating behavior and it is needed to maintain highway roadside noise to this threshold level.

• The Korean Journal of Zoology
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• v.28 no.3
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• pp.137-150
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• 1985

The dorsal skin of Rana temporaria dybowskii Guenther was examined under electron microscope. The results of the fine structures in the xanthophores, iridophores and melanophores were as follows: Xanthophores: Xanthophores were filled with pterinosomes and carotenoid vesicles. Type I pterinosomes had a clear limiting membrane. Type II pterinosomes had the inner fibrous structures. Tyep III pterinosomes were characterized by a few superficial lamellae and type IV pterinosomes by multiple concentric lamellae. Especially typical type II and type III pterinosomes were evenly distributed in the cytoplasm. Iridophores: Iridophores were situated between a xanthophore and a melanophore in the outer part of the dermis just below the basement membrane. Iridophores were filled with reflective platelets, each of which is rectangular and convex lens-like in shape. These platelets were closely contiguous and leave no interspace between them. Endoplasmic reticulum and a few mitochondria were observed in the supranuclear cytoplasm. Melanophores: Dermal melanophores contained numerous melanosomes. The dendritic precesses of the melanophore containing the melanin granules extented up the lateral sides of the iridophore. Epidermal melanophores were filled with melanin granules which appered as the same electron density. A few melanin granules were observed in a cornified surface cell.

• Animal cells and systems
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• v.1 no.1
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• pp.99-105
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• 1997

Using three species of Korean frogs (Rana dybowskii, R. rugosa and R. nigromaculata), the annual spermatogenic pattern, the seasonal changes in the steroidogenic competence, and responsiveness of testis to gonadotropins in terms of testosterone secretion in vitro were examined. The spermatogenic pattern of R. dybowskii was classified as a discontinuous type since spermatogenesis stops completely after spawning in late winter (February) until mid-summer (July). In contrast, the pattern of R. nigromaculata and R. rugosa was classified as a potent continuous type since sperm was always present in the seminiferous tubules all year round. In all three species, the levels of testicular testosterone and that of testosterone secreted by testis following in vitro culture were very low in late summer (August), but increased thereafter until winter (hibernation period). Interestingly, responsiveness of testis in vitro to gonadotropins in terms of testosterone secretion increased markedly in November (early hibernation period). Specifically, bullfrog LH was more effective than FSH in stimulating the secretion of testosterone by frog testis in vitro during hibernation period. This fact suggests that testosterone secretion by testis during hibernation is at least regulated by the pituitary gonadotropin rather than environmental factors. Taken together, the data presented here suggest that testicular cycles of three species of Korean frogs are closely linked to their females breeding cycles, and are eventually controlled by various environmental cues.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.694-704
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• 2016

Various infectious and parasitic diseases are known to be the main factors that cause decline in the global amphibian population. In Korea, commercial frog farms have been running since 2005. However, until now, studies on diseases including studies on parasitic diseases that occur in farm frogs have not been conducted. In this study, we studied and compared the acanthocephalan infection rates and the number of parasites in the body cavity, stomach, and small and large intestines of the Dybowskii's brown frogs collected from inside and outside the frog farms in Inje, Goesan, Gongju and Boryeong. In addition, we classified the acanthocephalan parasites into genera by analyzing their nuclear 18S rRNA genes. On an average, 51.7% of the investigated frogs were infected by acanthocephalans, which belong to the Centrorhynchus genus. The infection rate of the frogs collected in the Inje farm was 15%, significantly lower than those from the Goesan, Gongju and Boryeong farms. The rate in Goesan was 55%, which is lower than Gongju (80%) and Boryeong (90%) although it is not statistically significant. No difference was found in the infection rate and in the number of parasites in male and female frogs and between the groups collected from inside and outside of the farms. The number of infected parasites negatively correlated with the body condition of the frogs. The most parasites were found in the stomach followed by the small and large intestines and the body cavity. This study is the first report on the Centrorhynchus acanthocephalan infection of amphibians in Korea and it suggests the necessity for acanthocephalan parasite management and for conducting further disease-related studies in commercial frog farms.