• 한국환경생태학회지
• /
• 제33권2호
• /
• pp.178-186
• /
• 2019

국내에 서식중인 청개구리의 배아를 활용하여 농약류 3종의 독성평가를 위해 FETAX(Frog Embryo Teratogenesis Assay-Xenopus) 기법에 따라 청개구리(Hyla japonica)의 배아를 배양하면서 Benomyl(살균제), Carbofuran(살충제), Thiobencarb(제초제)의 효과를 probit 분석법으로 조사하였다. 그 결과, Benomyl, Carbofuran, Thiobencarb의 농도에 의존하여 유생의 체장 길이는 감소하고 치사율과 기형율은 증가하였다. Benomyl, Carbofuran, Thiobencarb의 teratogenic concentration($EC_{50}$)은 각각 1.00, 0.58, 4.75mg/L을 나타내어 Carbofuran이 기형유발에 가장 민감하게 반응하였으며, embryo lethal concentrations($LC_{50}$)은 7.04, 28.71, 16.12mg/L을 나타내어 Benomyl이 가장 낮은 농도에서 배아를 치사하는 것으로 나타났다. Teratogenic index($TI=LC_{50}/EC_{50}$)는 Benomyl 7.04, Carbofuran 49.50, Thiobencarb 3.39를 나타내어 TI값이 모두 기형유발물질로 판단하는 기준인 1.5 이상을 나타내어 시험에 사용된 농약류 3종은 최기형성 물질로 판단되며 Carbofuran이 가장 강력한 최기형성물질로 작용함을 알 수 있었다.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• 제2권2호
• /
• pp.114-119
• /
• 2021

To restore the Gold-spotted pond frog (Pelophylax chosenicus), a Korean endangered frog, 600 captive-reared individuals were reintroduced between August and September 2019 into an aquatic garden in the National Institute of Ecology where P. chosenicus had previously inhabited. After reintroduction, six post-release monitoring sessions were conducted from August 2019 to May 2020. Monitoring was performed using three methods (counting calls, observation, and capture) from sunset to midnight near release sites, eliminating potential threat factors. Snout-vent lengths and body weights of recaptured individuals were measured before they were released immediately. We noted that both snout-vent lengths and body weights of recaptured individuals were slightly higher than those before. The average recapture rate was 4.66%. Reintroduced frogs were recaptured at the last monitoring session conducted in May 2020, indicating that these reintroduced frogs hibernated during the winter successfully. We found that these reintroduced frogs successfully settled after release. This result will be useful for establishing management strategies for endangered frogs in Korea. Particularly, post-release monitoring could be an essential approach in the restoration program of a target species.

• BMB Reports
• /
• 제29권4호
• /
• pp.372-379
• /
• 1996

Components I and II (CI&II) are major phosphoproteins in the frog rod outer segments (ROS) of retina, whose phosphorylation is light- and cyclic nucleotide-dependent. Although it was reported that CI & II could be chemically cross-linked to ${\beta}{\gamma}-subunit$ of transducin (${\beta}{\gamma}_t$), it was not clear whether CI&II physically interact with ${\beta}{\gamma}_t$, under native conditions. CI&II extracted by hypotonic washing fo ROS membranes showed an overlapped migration with ${\beta}{\gamma}_t$, in sucrose density gradient centrifugation. The elution profile of CI&II in the peripheral membrane fractions from gel filtration chromatography also overlapped that of ${\beta}{\gamma}_t$. These hydrodynamic parameters indicate that the native molecular state of CI&II in the peripheral membrane fraction appears to be within a complex, most likely with ${\beta}{\gamma}_t$. CI&II coeluted with ${\beta}{\gamma}_t$, showed no phosphorylation by endogenous kinase which phosphorylates a serine of CI&II in other fractions. The purified CI&II were not able to inhibit trypsin-activated cGMP-phosphodiesterase, and CI&II were not recognized by a monoclonal antibody against the ${\gamma}-subunit$ of transducin, indicating that CI&II are not y-subunit of PDE or transducin. Thus, it is likely that native CI&II, which undergo a light-dependent phosphorylation/dephosphorylation cycle, can associate with ${\beta}{\gamma}$, in frog photoreceptor membranes, and the complex formation has an inhibitory effect on the endogenous phosphorylation of CI&II.

• 한국동물위생학회지
• /
• 제37권3호
• /
• pp.203-212
• /
• 2014

Frog culture industry is not yet familiar but has much potential. Generally, in farm, the population density is higher than that of in nature and frog farm is not the exception. But when population density is high, it can easily leads to stressful condition, poor sanitation. When a disease occur, it is a primary factor that makes the population more susceptible and the results more grave. Because of severe Rhabditoidea- helminth infection and subsequent bacterial septicemia, 50~70% of the total population had been died in a farm in Jeong-sun in Gangwon-do and Chungju in Chungcheongbuk-do from late June, 2012 to September, 2012. Diseased frogs showed ruptured lung, bloody ascites, liver discoloration, myocardium weakness, congested kidney, microcytic anemia and so on. Enterobacteriacea, Citrobacter.sp, Cupriavidus metallidurans, Acinetobacter.sp were isolated as major bacterium that had caused septicemia in frogs. Among isolated bacterium, Cupriavidus metallidurans, Ewingella americana, Shewanella aquimarina and Pseudoalteromonas sp. have not reported as potential pathogens in frogs before. It is a good example that severe helminth infection in frogs can lead to secondary infection of bacteria.

• 약학회지
• /
• 제32권2호
• /
• pp.129-136
• /
• 1988

Effects of the selective alpha-adrenoceptor agonists, clonidine, oxymetazoline and phenylephrine, on heart rate and contractile force were investigated in the isolated frog atria and it was attempted to examine the influence of adrenoceptor antagonist upon those. Clonidine produced dose-dependent negative chronotropic and positive inotropic effects. The negative chronotropic effect was significantly attenuated in the presence of prazosin and yohimbine but not propranolol. The positive inotropic effect was significantly attenuated by prazosin, yohimbine and propranolol. Oxymetazoline produced dose-dependent negative chronotropic and inotropic effects. The negative chronotropic effect was significantly attenuated in the presence of prazosin, which was partially augmented by yohimbine but was not affected by propranolol. The negative inotropic effect was not affected by propranolol but it was partially augmented by yohimbine and was partially attenuated by prazosin. Phenylephrine produced dose-dependent positive chronotropic and inotropic effects. The positive chronotropic and inotropic effect were significantly attenuated in the presence of propranolol but were not affected by prazosin and yohimbine. These results suggest that the negative chronotropic effect by clonidine and oxymetazoline is mediated by alpha-adrenoceptors, the positive chronotropic and inotropic effects by phenylephrine are mediated by beta-adrenoceptors, and alpha-adrenoceptors mediated the inhibitory chronotropic responses exists in the isolated frog atria.

• Archives of Pharmacal Research
• /
• 제16권2호
• /
• pp.83-88
• /
• 1993

opioid pure agonists, morphine, meperidine and methadone, were used to investigate the effect on the opioid receptor of fron sciatic nerve fibers using sucrose gap apparatus. When applied extracellularly by perfusion, morphine, methadone and meperidine significantly depressed the amplitude of the action potential in frog sciatic nerve fibers as a dose-dependent $(10^{-10}\;M-10^{-2}\;M)$ manner. The depression with morphine or methadone was partially antagonized by the simultaueous treatment with a lower $(10^{-10}\;M-10^{-8}\;M)$ concentration of naloxone, but that of meperidine was not blocked. When the three opioid agonists were applied intracellularly by placing it in a compartment with a cut end of the sciatic nerve fibers, all of themn depressed the amplitude of the action potentials by similar potency, and these reductions significantly blocked by pretreatment of lower concentration $(10^{-10}\;M-10^{-8}M)$ of naloxone. These results support the previous findings by other workers that the stereospecific opioid receptors of this preparation are located on or near the intracellular opening of the sodium channels which are sensitive to naloxone.

• Animal cells and systems
• /
• 제16권3호
• /
• pp.260-267
• /
• 2012

Calling behavior is often used to infer breeding patterns in anurans. We studied the seasonal and diel calling activities of anuran species in a wetland in central Korea to determine the calling season and to evaluate the effects of abiotic factors on male calling. Acoustic monitoring was used in which frog calls were recorded for a full day, once a week, throughout an entire year. Using acoustic monitoring, we identified three frog species in the study site. Males of Rana dybowskii called in late winter and early spring; we thus classified this species as a winter/spring caller. The results of binary logistic regression showed that temperature, relative humidity, and 1-day lag rainfall were significant factors for male calling in R. dybowskii. Temperature and relative humidity were important factors for the calling activity of R. nigromaculata, whereas 24-h rainfall and 1-day lag rainfall were not significant. Thus, we determined R. nigromaculata to be a summer caller independent of weather. In Hyla japonica, relative humidity, 24-h rainfall, and 1- day lag rainfall were significant for male calling, suggesting that this species is a summer caller dependent on local rain.

• Journal of Ecology and Environment
• /
• 제45권1호
• /
• pp.10-16
• /
• 2021

Background: Ranavirus is an emerging infectious disease which has been linked to mass mortality events in various amphibian species. In this study, we document the first mass mortality event of an adult population of Dybowski's brown frogs (Rana dybowskii), in 2017, within a mountain valley in South Korea. Results: We confirmed the presence of ranavirus from all collected frogs (n = 22) via PCR and obtained the 500 bp major capsid protein (MCP) sequence from 13 individuals. The identified MCP sequence highly resembled Frog virus 3 (FV3) and was the same haplotype of a previously identified viral sequence collected from Huanren brown frog (R. huanrenensis) tadpoles in South Korea. Human habitat alteration, by recent erosion control works, may be partially responsible for this mass mortality event. Conclusion: We document the first mass mortality event in a wild Korean population of R. dybowskii. We also suggest, to determine if ranavirus infection is a threat to amphibians, government officials and researchers should develop continuous, country-wide, ranavirus monitoring programs of Korean amphibian populations.

• 한국동물학회지
• /
• 제17권1호
• /
• pp.43-50
• /
• 1974

1. 개구리 피부점액선의 점액질은 중성, 약산성 및 강산성황화점액질을 포함하되, 선경부 세포에는 중성점액질만이, 선체부 세포에는 3종류의 점액질 성분이 혼재한다. 2. 피부 점액선의 점액질은 건조상태에서 현저히 감소하며 성분별로 볼 때 산성점액질에 비하여 중성점액질이 더욱 심한 영향을 받는다. 3. 점액선 세포내 점액질은 건조상태에 노출된 시간에 따라 점액질 성분상의 변화는 없다. 4. 이상과 같은 현상은 몸의 항상성을 유지하기 위한 생체적응현상의 일단이라고 생각된다.

• 한국동물학회지
• /
• 제18권3호
• /
• pp.107-114
• /
• 1975

1. 개구리 피부 장액선의 분비과립은 중성과 약산성점액질이 존재한다. 2. 피부 장액선의 분비과립은 건조상태에서 현저히 감소하며 성분별로 점액질을 볼 때 중성점액질이 산성점액질보다 더 심한 영향을 받는다. 3. 장액선의 내강내에 있는 분비과립내 점액성분은 건조상태의 노출시간에 따라 성분상의 변화는 없다. 4. 이상과 같은 현상은 체항상성을 유지 하기 위한 생체적응현상의 일단이라고 생각한다.