• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.191.1-191
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• 1997

No Abstract, See Full Text

• The Journal of the Acoustical Society of Korea
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• v.36 no.6
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• pp.401-406
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• 2017

This paper presents the performance assessment of several key algorithms conducted for amphibian species sound classification. Firstly, 9 target species including endangered species are defined and a database of their sounds is built. For performance assessment, three feature vectors such as MFCC (Mel Frequency Cepstral Coefficient), RCGCC (Robust Compressive Gammachirp filterbank Cepstral Coefficient), and SPCC (Subspace Projection Cepstral Coefficient), and three classifiers such as GMM(Gaussian Mixture Model), SVM(Support Vector Machine), DBN-DNN(Deep Belief Network - Deep Neural Network) are considered. In addition, i-vector based classification system which is widely used for speaker recognition, is used to assess for this task. Experimental results indicate that, SPCC-SVM achieved the best performance with 98.81 % while other methods also attained good performance with above 90 %.

• The Korean Journal of Zoology
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• v.39 no.3
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• pp.266-272
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• 1996

Experiments were carried out to ascertain whether gonadotropin or a phorbol ester (12-O-tetradecanoyl phorbol-13-acetate, TPA) induces oocyte ovulation and stimulates prostaglandin synthesis by Rana ovarian follicles in vitro. Rana nigromaculata collected from underground in spring were utilized for the present experiment. Treatment of frog pituitary homogenate (FPH) or TPA to ovarian fragments in culture induced oocyte ovulation in a dose dependent manner and stimulated prostaglandin F2a (PGF$_2$$\alpha$ synthesis. Both treatruents were more effective in inducing the ovulation and PGF$_2$$\alpha$ secretion by the follicles obtained in May than those in April. A Protein kinase C inactivator, 1-(5-isoquinolinyl-sulfonyl)-2-methyl-piperazine (H-7), or cyclooxygenase inhibitor, indomethacin (IM) suppressed the FPH- or TPA-induced PGF$_2$$\alpha$ production, but IM failed to suppress the FPH- or TPA-induced ovulation. Time course of oocyte ovulation and PGF$_2$$\alpha$ secretion by FPH and TPA treatments were very similar to each other. FPH stimulated progesterone secretion by the follicle but TPA failed to do so. Taken together, the data presented here suggest that protein kinase C (PKC) in follicle play a role in the ovulation process of Rana nigromaculata, probably via prostaglandin synthesis.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.13-20
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• 2007

Fauna of Shinpo nuclear powerplant site were surveyed during Feb 27-Mar 4, 2003 as a part of ecological environmental survey. This area is well dominated by coniferous trees (Pinus densiflora) ranging 15-50 years. In the shoreline black pine (Pinus thungergii) is the dominant species and was planted for wind protection. Around Shinpo areas inside 50 km in radius was found 33 mammal species (3 orders, 15 families), and amphibian-reptiles 6 species (2 orders, 3 families) were recorded. Natural monument in the areas were estimated 6 species of mammals and one species of reptiles. Although the habitat of Shinpo area is deteriorated due to deforestation, illegal hunting, etc. the fauna seems to be rich in species. Despite the sudden halt of KEDO project the conservation efforts and continuous monitoring are required considering a continuation of the project.

• The Journal of the Acoustical Society of Korea
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• v.37 no.1
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• pp.60-65
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• 2018

In this paper, a covariance matrix and modulogram are proposed for realizing amphibian sound classification using CNN (Convolutional Neural Network). First of all, a database is established by collecting amphibians sounds including endangered species in natural environment. In order to apply the database to CNN, it is necessary to standardize acoustic signals with different lengths. To standardize the acoustic signals, covariance matrix that gives distribution information and modulogram that contains the information about change over time are extracted and used as input to CNN. The experiment is conducted by varying the number of a convolutional layer and a fully-connected layer. For performance assessment, several conventional methods are considered representing various feature extraction and classification approaches. From the results, it is confirmed that convolutional layer has a greater impact on performance than the fully-connected layer. Also, the performance based on CNN shows attaining the highest recognition rate with 99.07 % among the considered methods.

• The Korean Journal of Zoology
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• v.31 no.1
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• pp.29-34
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• 1988

In order to investigate the role of nuclei and cytoplasm in early embryogenesis, interspecific nuclear transplantation was carried out Nuclei of one species of amphibian was transplanted into enucleated egg of another species. In interspecific hybrids between Rana species, development was arrested before or right after the dorsal lip formation. In intergenetic hybrids between Rana, Xenopus and axolod, developmental arrest took place at late blastula stage. Comparing the developmental capacity of each nudeocytoplasmic hybrid, the more distantly related the species, the earlier does development arrest. The general rule is that nuclear transfers between any amphibian species will form a regulary cleaved late blastula. Two plausible factors relate to limitation of tite developmental capacity of nudeocytaplasmic hybrids. One is an irreversible change in grafted nuclei and another is tunctional incompatibility between the recipient cytoplasm and transplanted nucleus. The later is postulated a more possible cause of the arrestrnent.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.406-413
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• 2020

In this paper, to improve the classification accuracy of bird and amphibian acoustic sound, we utilize GLU (Gated Linear Unit) and Self-attention that encourages the network to extract important features from data and discriminate relevant important frames from all the input sequences for further performance improvement. To utilize acoustic data, we convert 1-D acoustic data to a log-Mel spectrogram. Subsequently, undesirable component such as background noise in the log-Mel spectrogram is reduced by GLU. Then, we employ the proposed temporal self-attention to improve classification accuracy. The data consist of 6-species of birds, 8-species of amphibians including endangered species in the natural environment. As a result, our proposed method is shown to achieve an accuracy of 91 % with bird data and 93 % with amphibian data. Overall, an improvement of about 6 % ~ 7 % accuracy in performance is achieved compared to the existing algorithms.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.53-62
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• 1990

Fully grown amphibian oocytes undergo their maturation (germinal vesicle breakdown, GVBD) during in vitro follicle culture when they are stimulated with frog pituitary homogenate (FPH) or progesterone. Present experiments were designed to determine whether proteolytic enzymes are involved in the regulation of the matunation process. Treatment of a $\alpha$ -chymoiyypsin inhibitor, N a -tosyl-L-phenylalanine-chloromethyl-ketone(TP) to the oocytes exhibited a biphasic phenomenon, the induction of the maturation without added hormone at relatively low doses (0.001-1 $\mu$M) and inhibition of the hormone induced oocyte maturation at a high dose (100 $\mu$M). Treatment of a trypsin inhibitor, N a -tosyl-L-lysine-chloromethyl ketone(TLCK) to the oocytes did not induce the maturation, but rather suppressed the hormone induced oocyte maturation in a high dose(100 $\mu$ M). Treatment of exogenous iyypsin to the oocyte induced their maturation without added hormone in a dose dependent manner (0.001-1 $\mu$ M). The data presented here indicate that some proteolytic enzymes play a role in the regulation of the maturation(meiotic arrest or reinitiation) in amphibians.

• Animal cells and systems
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• v.10 no.4
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• pp.203-209
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• 2006

Azoles are widely used antifungal agents, which inhibit the biosynthesis of fungal cell-membrane ergosterol. In this study, using an amphibian follicle culture system, the effects of azoles on follicular steroidogenesis in frogs were examined. Itraconazole (ICZ), clotrimazole (CTZ) and ketoconazole (KCZ) suppressed pregnenolone ($P_5$) production by the follicles ($ED_{50};\;0.04_{\mu}M,\;0.33_{\mu} M,\;and\;0.91_{\mu}M$, respectively) in response to frog pituitary homogenates (FPH). However, fluconazole (FCZ), miconazole (MCZ) and econazole (ECZ) were not effective in the suppression of $P_5$ production. Not all the azoles examined suppressed the conversion of exogenous $P_5$ to progesterone ($P_4$) (by $3{\beta}$- HSD) or $P_4$ to $17{\alpha}$-hydroxyprogesterone ($17{\alpha}$-OHP) (by $17{\alpha}$-hydroxylase), or androstenedione (AD) to testosterone (T) (by $17{\beta}$-HSD). In contrast, CTZ, MCZ and ECZ in medium partially suppressed the conversion of $17{\alpha}$-OHP to AD (by C17-20 lyase) ($ED_{50};\;0.25{\mu} M,\;4.5{\mu}M,\;and\;0.7{mu}M$, respectively) and CTZ, KCZ, ECZ and MCZ strongly suppressed the conversion of exogenous T to estradiol ($E_2$) (by aromatase) ($ED_{50};\;0.02{\mu}M,\;8{\mu}M,\;0.07{\mu}M,\;0.8{\mu}M$, respectively). These results demonstrated that some azole agents strongly suppress amphibian follicular steroidogenesis and particularly, P450scc and aromatase are more sensitive to azoles than other steroidogenic enzymes.

• 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.