• Animal Systematics, Evolution and Diversity
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• v.12 no.3
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• pp.253-264
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• 1996

The ultrastructure of spermatozoa in urodeles and primitive anurans was examined and compared. The spermatozoa of urodeles are characterized by seven plesiomorphies in subacrosomal cone, endounclear canal. perforatorium, ring, marginal filament, undulating membrane and tail axis. Most primitive anuran spermatozoa have no marginal filament, subacrosomal cone and ring structure with the exception of having the subacrosomal cone in Ascaphus and the ring in Discohlossus as compared with those of urodeles. Persistence of the subacrosomal cone and the ring structure is typical in most urodeles and is further linked with the primitive anurans. Therefore, these characters are regarded as symplesiomorphies in urodeles and primitive anurans. The organization of sperm tail, endounclear canal and perforatorium indicates a close phylogenetic relationship between urodeles and the primitives anurans.

• Korean Journal of Environmental Biology
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• v.26 no.1
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• pp.22-29
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• 2008

Bombina orientalis, or Korean fire-bellied toad is belonging to Class Amphinia, Order Anura, Family Bombinatoridae, Genus Bombina. Ecological characteristics, such as small size, slow moving and swimming, gentle attitude to other species, under laboratory and/or wild condition lead the toad as suitable experimental animals with easy handling. Seasonal reproductive biology except breeding season (usually from Apr. to late Jun.) are unknown still caused by sampling methods for hibernating specimens have not been established yet. Most species of amphibian, include B. orientalis, are declined around the world related with global warming, therefore, wild caught specimen for any purposes must be limited controled soon. Even though, some pre-studies of biotope for increasing biodiversity have been reported, construction of an artificial biotope to get natural breeding cycling specimen for study of amphibian reproduction is unique modelling and only trial. In an effort to set year-round sampling for study of reproduction of B. orientalis, we suggest protocols for planning, construction manual and SOP(Standard Operation Process) to manage amphibian biotope. During pilot operation of a designed and constructed biotope, the seasonal acclimation during winter hibernation of B. orientalis were successful. It will be helpful for studying the reproductive biology of wild amphibians in temperate region and allow to get reasonable research conditions in amphibian laboratory.

• The Korean Journal of Zoology
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• v.35 no.4
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• pp.518-525
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• 1992

본 연구에서는 horizontal clinostat과 원심분리 방법의 이용으로 각각 저중력 상태($\mu$G)와 고중력 상태(3G)를 유도하여, 중력장의 변화가 양서류 수정란의 초기 형태 형성에 미치는 영향을 북방산개구리(Rano dybows비름를 대상으로 조사하였다. 중력장의 변화는 첫번째 수평 분열인 제3분열면의 위치에 영향을 미쳤다. 즉 저중력 상태에서는 분열면이 적도면 근처에서, 또 고중력 상태에서는 분열면이 동물극 근처에서 형성되었다. 이와 같은 변화는 포배기로 이어져 할강의 위치와 동물극 정단 세포층 수에 영향을 미쳤다. 즉 저중력에 노출된 포배는 정상배(1G)에 비해 할강이 중앙에 위치했으며 동물극 정단의 세포층 수가 증가하는 반면 고중력에 노출된 포배는 할강이 보다 동물극 폭에 위치했으며 동물극 정단의 세포층 수도 감소하였다. 그러나 낭배기에 도달하면 동물극 정단 세포층 수의 차이는 정상 상태로 조절되었다. 한편 중력장의 변화는 낭배기에 이르는 발생 속도와 원구상순부의 위치를 변경시켰다. 낭배기 이후의 발생 단계에서 중력에 의한 변화로는 tail fin circulation(stage 22)시기의 머리크기의 변화를 들 수 있다. 이상의 결과로 무미 양서류의 초기 형태 형성은 중력장에 의해 변형될 수 있으며 이러한 변화는 발생이 진행됨에 따라 조절되는 것으로 보인다.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.582-590
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• 2018

Although there are many studies of the effect of climate change on the breeding phenology and community diversity of amphibians, the studies of variations in reproductive population size of individual species according to climate change are still lacking. We examined the effect of climate change on the reproductive population size of Rana huanrenensis and Hynobius leechii, which bred in mountain valleys, by surveying the reproductive population of the two species between 2005 and 2012 and analyzing the correlation between the variation of the outdoor population and the surrounding climate change factors, obtained from a meteorological observatory located at 5.6 km from the study site. The size of the reproductive population of the two species commonly fluctuated with aan pproximately 3.5-year cycle. That of H. leechii, in particular, decreased significantly over eight years. The air temperature tended to more closely relate with the reproductive population size of R. huanrenensis as was the case of the precipitation with that of H. leechii. The yearly mean highest temperature and spring mean temperature variation consistently decreased over the eight years, and the latter was related with the significantly decreased size of H. leechii reproductive population. These results showed that recent climate change directly could affect the reproductive population size of amphibians, particularly H. leechii, which breeds in mountain valleys.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.94-102
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• 1990

In Xenopus laevis the cranial myotomes, W, X, Y and Z represent transient embry-specific structures since they undergo reduction" in the later stage of development. An extensive set of expertmental studies was undertaken in order to discriminate whether the cranial myotomes perform a programmed autonomous death or reduction" by the influence from surrounding tissue such as otic vesicle. Removal of the neighboring otic vesicle did not affect WXYZ degeneration. Grafting the otic vesicle to novel site along the somite file did not induce local myotome degenration. When anterior-most somitic primordia were relocated to the trunk somite region, they underwent reduction eventually. Likewise, with the transplantation of posterior somite forming region into the anterior, autonomous differentiation pafferns were observed. And the cullture of presumptive somitic tissue revealed that WXYZ might degnerate like in vivo. It is therefore concluded that the cranial myotomes of Xenopus laevis exhibit an autonomous cell death during later embryogenesis.yogenesis.

• The Korean Journal of Zoology
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• v.3 no.2
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• pp.13-18
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• 1960

For the study on the sex ratio in natural populations of the different localities, the amphibian species were collected as the materials at the seven localities in Korea, and were obtained the following results. The sex ratios of each amphibian species suggest that each has it's own specific sex rations the following list. Rana nigromaculata H. : 109-39, Rana rugosa SCH. : 67.44, Rana temporaria coreana O. : 158.45, Hyla arborea japonica G. : 137.70. In Rana nigromaculata H. the average sex ratio was 109.39 as the above list, and its was reached statistically significant level according to the different localiies. The sex ratio was generally higher in the eastern area than that in the western area in this country. The sex ratio of the adult frogs of Rana nigromaculata H. was 135.18 , and it has a statistically significant level by each locality but the sex ratio of the younger frogs of the same species was 100.97 which was a little lower than that in the adult, and it was not laid at a significant level according to the localities. There is no doubt that the difference of sex ratios according to the localities was mainly due to the different ratios of the adult frogs which were effected on the constitution of sex by environmental factors in each locality.

• Hwankyungkyoyuk
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• v.19 no.1 s.29
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• pp.104-115
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• 2006

This study was conducted to investigate whether attitudes and recognitions of middle and high school students regarding environmental concerns were improved after anuran call monitoring. It was a step toward monitoring local environmental changes with anuran calls. Three-striped pond frogs (Rana nigromaculata), Bullfrogs (R. catesbeiana), and Narrow-mouthed toads (Kaloula borealis) were surveyed to determine local abundance and distribution of them in 12 study sites using their advertising calls. A published booklet, which contains morphological, physiological, ecological, and acoustic information on amphibian species and methods of monitoring anuran calls were provided to monitoring students for identifying the three species. Pretest-posttest were conducted before and after monitoring from 10 April to 28 August in 2005 to determine how the monitoring students changed their attitudes on environmental issues, increased knowledges on amphibians, and improved the understanding on the cause and effect of declining amphibian populations. The amphibian monitoring program was effective to improve the students' attitudes towards conserving environments as well as the students' knowledge on general behavior and ecology of various amphibian species although their understanding about various environmental problems was not. In addition, the program increased the students' understanding on the problems of declining amphibian populations.

• The Korean Journal of Zoology
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• v.27 no.2
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• pp.93-102
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• 1984

Xenopus laevis eggs were de-jellied and manually manipulated to remove their vitelline membranes. They were then positioned in a variety of orientations re. gravity. That is the future ventral side was located upwards (opposed gravity) or downwards (faced gravity). Development through the tailbud stage was observed and the frequency of double axes formation recorded. Orientation of the egg re. its natural polarity was not an important factor in generating double axes. Its physical structure (flattened re. spherical), however, appeared to be important in determining the frequency of twinning. These observations give insights into the mechsnism of polarity establishment in anuran eggs, and provide methods which should be useful for studies on primary embryonic induction.

• Environmental Mutagens and Carcinogens
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• v.10 no.1
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• pp.25-32
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• 1990

포배단계의 북미산 표범개구리 Rana pipiens의 핵을 국내종 북방산개구리 Rana dybowskii의 무핵난에 이식하여 형성되는 nucleocytoplasmic hybrid 개체는 초기 낭배시기를 전후하여 치사하는 조합임이 핵치환 실험에 의하여 밝혀졌다. 이들의 치사원인이 이질세포질의 존재에 의한 일시적 현상인지 또는 발생도중 핵내에 일어난 영구적 변화에 의한 것인지를 조사하기 위한 노력의 일환으로 치사직전 개체의 염색체를 분석한 결과, 염색체의 수와 염색체의 일부분에 구조적 이상이 다양하게 관찰되었다. 따라서 이질세포질에서 DNA의 이상복제가 진행되었음을 나타내고 있으며 그 결과 비정상적 염색체를 가진 할구의 형성과 부분 난할등이 유발되어 결국 치사하는 것으로 사료된다. 또한 nuclocytoplasmic 개체의 lethality 는 정상개체와의 접촉에 의해 교정되지 않는 조직의 내적 특성임이 hybrid의 조직을 정상 embryo로 이식시킨 실험을 통해 명확히 밝혀졌다.

• The Korean Journal of Zoology
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• v.27 no.3
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• pp.127-136
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• 1984

The specification of dorsal/ventral axis in the egg of Xenopus laevis was investigated as a series of oblique orientation to gravity by tilt and clinostat. The results are as follows. (1) If the eggs were oriented, in the early period after fertilization, to novel gravity by $15^\\circ, 30^\\circ, 45^\\circ$ and $60^\\circ$ tilt until gastrula stage, the site of involution was usually formed in the OpG side (the side opposing gravity). As the degree of tilt was raised from $15^\\circ to 60^\\circ$, the rate of relocation of the involution site was proportionally increased. (2) When UV-irradiated eggs were tilted period to first cleavage by $15^\\circ, 30^\\circ, 45^\\circ$ and $6\^\\circ$, the effect of UV syndrome was rescued, and the extent of rescue was propotional to the tilt degree. (3) The fertile eggs were loaded on the clinostats of several speeds. In the range of low speeds between $0.45 \\sim 9.0$ rph, the location of dorsal lip was dependent on the direction of rotation, and in $40 \\sim 360$ rph, lip was formed at a random position. In addition, some of the tadpoles experienced with clinostat showed the typical syndrome of "dorsal axis reduction". The above results were discussed regarding the mechanism of the establishment of dorsal/ventral palarity. palarity.