• Journal of Photoscience
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• v.7 no.3
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• pp.115-121
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• 2000

Although there are high concentrations of zinc and taurine in ocular tissue, their exact role and correlation in the visual process are not clear. The purpose of present study was to clarity this point using electroretinogram (ERG) recording and spectrophotometer measurements before and after zinc and taurine treatment in bullfrog's eye. The optimal zinc concentration used in this study was 10$^{-2}$ M ZnCl$_2$120 ${mu}ell$/12$m\ell$ ringer solution while the optimal turine concentration was 10$^{-2}$ M taurine 12${mu}ell$/12$m\ell$ ringer solution. For the effects of zinc and taurine on the retinal function, the changes of ERG parameters (especially threshold and b-wave) and absorption spectra were observed before and after treatment. It is noteworthy that high concentrations of zinc and taurine present in the retinal pigment epithelium and the retina. Our results indicate that dark-adapted ERG threshold became elevated and the peak amplitude of b-wave was increased with zinc and taurine treatment. Furthermore there are some synergism effects between zinc and taurine as a result of co-treatment. In spectral scan, absorbance increment due to zinc and taurine treatment was shown over the whole range of spectral range (300-750 nm) with some differences in absorbance increment depending on the case of treatment. As the results of above we believe that zinc and taurine, which are abundant in the retinal pigment epithelium and the retina particularly, may be essential factors for visual process, have some synergism with each other and be required to improve the visual sensitivity during visual adaptation.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.532-532
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• 2003

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.226.2-226
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• 1998

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1999.04a
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• pp.70.2-70
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• 1999

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.221.2-221
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• 1996

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.187-188
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• 2000

No Abstract, See Full Text

• Proceedings of the Korean Society of Life Science Conference
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• 2003.10a
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• pp.154-155
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• 2003

• Journal of Photoscience
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• v.7 no.4
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• pp.161-167
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• 2000

Temperature-dependent electroretinogram responses were investigated in the dark adapted bullfrog eyes within the physiological temperature range 0-40$\^{C}$. In hypothermic process(25→0→25$\^{C}$), the amplitude of b-and c-wave decreased with lowering the temperature again. Both b-wave amplitude and threshold responses were maximal around 15$\^{C}$ during the temperature increment. Upon warming to room temperature again (25$\^{C}$), the b-wave amplitude was approximately doubled as compared to that of control without temperature changes. During the hyperthermic process (25→40→25$\^{C}$), however, the responses decreased with warming, and the wave amplitude failed to recover by cooling to 25$\^{C}$ again. As describe above, the recoveries of ERG in both processes show the striking difference. The hypothermia induces the amplification of the b-wave, that is, enhances the retinal function with the temperature recovery toward room temperature. While the hypertherima produces the decrease of the b-wave even though recovered to room temperature, which indicates an irreversible retina. The morphological alteration is shown both hypothermic and hyperthermic process, such as an appearance of large vacuoles and degenerating outer segments, more intense in hyperthermia, similar to light induced damage.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.1
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• pp.23-33
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• 2007

It has been reported high concentrations of zinc and taurine in ocular tissue, especially the retina-choroid, and the presence of physiological levels of zinc and taurine in these tissues seem essential for their normal function. In addition, several studies have reported temperature as another effector to the visual sensitivity. But, in spite of many studies, there are still remained many questions about their function and correlation in visual adaptation system. The purpose of present study was to clarify these points using electroretinogram(ERG) recording and absorption spectra scanning, before and after zinc and taurine treatments and hypothermic-effect in bullfrog(Rana catesbeiana) which is one of the poikilothermal animal. The optimal zinc concentration used in this study was determined $10^{-4}M$ while the optimal taurine concentration was 10-5 M, and temperature change for hypothermic-effect went through '$25^{\circ}C {\rightarrow}0^{\circ}C{\rightarrow}25^{\circ}C$'. In ERG recording, it is obtained that dark-adapted threshold became elevated and b-wave amplitudes was increased with zinc and taurine treatment and hypothermic-effect. In absorption spectra scanning, there is distinct absorbance increment over the whole spectral range(400~750 nm) after zinc and taurine treatment and hypothermic-effect. Furthermore there are some synergism effects between zinc and taurine as well as between zinc and hypothermic-effect as a result of co-treatment, respectively.

• The Korean Journal of Ecology
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• v.28 no.6
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• pp.375-382
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• 2005

The American bullfrog, Rana catesbeiana was imported from Japan for farming for the human consumption in 1970's and introduced populations were a great threat to native habitats in the pond and lake ecosystem. However, it is thought that the population of bullfrog has rapidly declined for past years in Korea. In this study, we investigated the intra-genetic diversity of R. catesbeiana habitated in Korea. The nucleotide sequences of 1,215bp mitochondrial ND1/tRNA region in bullfrogs sampled from 5 sites in Jeollanamdo were analyzed and compared to the original sequence of R. catesbeiara reported in Genbank. The nucleotide similarity between Korean and North American bullfrog was ranged from 98.7% to 100% based on kimura-2-parameter distance. In addition, bullfrogs analyzed in this study were clustered into two groups with one including Jangheung and the other including Gwangju populations in the neighbor-joining tree. North American R. catesbeiana was grouped in Jangheung cluster, indicating that there is the very low genetic difference between Korean and North American populations. The maximum parsimony tree in which North American R. catesbeiana was set as an outgroup suggests that Jangheung group represents the introduced population to Korea. Taken together, the results indicate that the population of R. catesbeiana in Korea has not segregated geographically yet, after the introduction.