• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.147-151
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• 2006

난생 생물의 알 생성유도 단백질인 비텔로제닌(viteILogenin, VTG)을 성숙한 암컷 황소개구리 (Rana catesbeiana)혈청으로부터 음이온 교환 크로마토그래피를 이용하여 정제 하였으며 정제한 비텔로제닌을 BALB/c mice에 주사하여 폴리크로날 항체를 생산하였고 이것은 protein A column으로 정제 하였다. 이렇게 정제된 폴리크로날 항체를 이용하여 황소개구리 비탈로제닌 측정용 효소면역측정법을 개발하였으며 그 측정 범위는 $12{\sim}1,560ng/mL$였다. 또한 이 효소면역측정법을 평가하기 위해 성숙한 수컷 황소개구리를 청정지역과 폐수처리장 하류 하천에서 서식하는 황소개구리 혈액 속의 비텔로제닌을 측정하였다. 그 결과 폐수처리장 하류 하천에 서식하는 수컷 황소개구리 비텔로제닌이 청정지역보다 현저하게 높게 유도됨을 알 수 있었다.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.543-553
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• 1992

Properties of unitary ATP-sensitive $K^+$ channels were studied using planar lipid bilayer technique. Vesicles were prepared from bullfrog (Rana catesbeiana) skeletal muscle. ATP-sensitive $K^+$ (K (ATP)) channels were identified by their unitary conductance and sensitivity to ATP. In the symmetrical solution containing 200mM KCI, 10mM Hepes, 1mM EGTA and pH 7.2, single K (ATP) channels showed a linear current-voltage relations with slight inward rectification. Slope conductance at reversal potential was $60.1{\pm}0.43$ pS(n=3)). Micromolar ATP reversibly inhibited the channel activity when applied to the cytoplasmic side. In the range of -50~＋50 mV, the channel activity was not voltage-dependent, but the channel gating within a burst was more frequent at negative voltage range. Varying the concentrations of external/internal KCl(mM) to 40/200, 200/200, 200/100 and 200/40 shifted reversal potentials to $-30.8{\pm}2.9$(n=3), $-1.1{\pm}2.7$(n=3), 10.5 and 30.6(mV), respecrivety. These reversal potentials were close to the expected values by the Nernst equation, indicating nearly ideal selectivity for $K^+$ over $Cl^-$. Under bi-ionic conditions of 200mM external test ions and 200mM internal $K^+$, the reversal potentials for each test ion/K pair were measured. The measured reversal potentials were used for the calculation of the releative permeability of alkali cations to $K^+$ ions using the Goldman-Hodgkin-Katz equation. The permeability sequence of 5 cations relative to $K^+$ was $K^+$(1), $Rb^+$(0.49), $Cs^+$(0.27), $Na^+$(0.027) and $Li^+$(0.021). This sequence was recognized as Eisenman's selectivity sequence IV. In addition, modelling the permeation of $K^+$ ion through ATP-sensitive $K^+$ channel revealed that a 3-barrier 2-site multiple occupancy model can reasonably predict the observed current-voltage relations.

• 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.31 no.1
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• pp.54-61
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• 2017

We investigate predation rates of larvae and juveniles of Rana catesbeiana by using six native predatory fishes and six birds to select effective species to ecological control and management of R. catesbeiana that is invasive alien species and affects seriously wetland in Korea. Among freshwater fishes, Pseudobagrus fulvidraco, Silurus asotus and Channa argus ate larvae and juveniles of R. catesbeiana, and prefer the former, however Opsariichthys uncirostris, Monopterus albus and Anguilla japonica didn't eat at all. Six experimental water birds, Cygnus columbianus, Cygnus cygnus, Anas crecca, Aix galericulata, Anas penelope and Anas formosa nerver ate them. We were able to confirm control of R. catesbeiana probability using the native predatory fishes in Korea wetland.

• Animal cells and systems
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• v.11 no.1
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• pp.1-8
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• 2007

Recently, we have shown that some endocrine disruptors, heavy metals, organotins and azoles suppressed steroidogenic enzymes such as P450 side-chain cleavage enzyme (P450scc) and aromatase in bullfrog ovarian follicles. In the present study, by using an amphibian ovarian follicle culture system, we examined the effects of these endocrine disruptors on maturation and ovulation of oocytes from Rana dybowskii in vitro. Ovarian fragments or isolated follicles were cultured for 24 h in a medium containing frog pituitary homogenate (FPH) or progesterone ($P_{4}$) with or without endocrine disruptors, and oocyte maturation (germinal vesicle breakdown, GVBD) and ovulation were examined. Among the organotins, tributyltin (TBT) strongly inhibited both FPH-and $P_{4}-induced$ oocyte maturation ($ED_{50}$:0.6 and 0.7 ${\mu}M$, respectively); however, tetrabutyltin (TTBT) and dibutyltin (DBT) showed only partial suppression, while monobutyltin (MBT) showed no inhibitory effect. All of the organotins suppressed $P_{4}-induced$ oocyte ovulation very effectively at a low concentration, and TBT and DBT exerted an inhibitory effect on FPH-induced ovulation. Among the heavy metals, mercury (Hg), cadmium (Cd) and cobalt (Co) were very effective in inhibiting FPH-induced oocyte maturation and ovulation, while lead (Pb), arsenite (As) and zinc (Zn) were less effective. However, all of the heavy metals suppressed FPH-induced oocyte ovulation at a high dose ($100{\mu}M$). Among the azoles, itraconazole (ICZ), ketoconazole (KCZ) and clotrimazole (CTZ) effectively inhibited FPH-induced oocyte maturation and ovulation, while econazole (ECZ), miconazole (MCZ) and fluconazole (FCZ) were considerably less effective. These results demonstrated that the abovementioned endocrine disruptors exhibited differential effects on oocyte maturation and ovulation in amphibian follicles and that the frog ovarian culture system could be used as an effective experimental tool to screen and evaluate the toxicity of various endocrine disruptors in vitro.

• Analytical Science and Technology
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• v.15 no.2
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• pp.149-156
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• 2002

In this study, the levels of DEHA, carbaryl, and amitrole contained in the fresh water fishes and amphibians were determined. The 31 sampling sites were selected including 29 sites along the several rivers and 2 sites from the well-known wet lands. The rivers consists of the Han, Nakdong, Kum, Youngsan, and other small scaled rivers. DEHA was detected from 10 sites, but carbaryl and amitrole were not detected at any sites. The highest average concentration of DEHA was determined from the Kum River by $52.7{\mu}g/kg$. In the detected 10 sites, the average concentration of DEHA from fishes was $40.0{\mu}g/kg$, and that from amphibians was $8.90{\mu}g/kg$ which indicates that 5 times more DEHA was observed from fishes than amphibians. The detection frequency from fishes was 10/62 while that from amphibians was 2/62, and the highest concentration from fishes was $95.5{\mu}g/kg$ (crucians from Kongjoo) and that from amphibians was $12.1{\mu}g/kg$ (bullfrog from Najoo). Among the 10 detected sites, 6 sites were agricultural area and the other 4 sites were semi-urban area.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.364-371
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• 2021

Public awareness of alien species can vary by generation, period, or specific events associated with these species. An understanding of public awareness is important for the management of alien species because differences in public awareness can affect the establishment and implementation of management plans. We analyzed digital texts on social media platforms, news articles, and internet search volumes used in conservation culturomics to understand public interest and sentiment regarding alien freshwater species. The number of tweets, number of news articles, and relative search volume to 11 freshwater alien species were extracted to determine public interest. Additionally, the trend over time, seasonal variability, and repetition period of these data were confirmed. We also calculated the sentiment score and analyzed public sentiment in the collected data using sentiment analysis based on text mining techniques. The American bullfrog, nutria, bluegill, and largemouth bass drew relatively more public interest than other species. Some species showed repeated patterns in the number of Twitter posts, media coverage, and internet searches found according to the specified periods. The text mining analysis results showed negative sentiments from most people regarding alien freshwater species. Particularly, negative sentiments increased over the years after alien species were designated as ecologically disturbing species.