• Fisheries and Aquatic Sciences
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• 제12권4호
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• pp.265-275
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• 2009

G Protein-coupled receptors (GPCRs) mediating wide ranges of physiological responses is one of the most attractive targets for drug development. Rhodopsin, a dim-light photoreceptor, has been extensively used as a model system for structural and functional study of GPCRs. Fish have rhodopsin finely-tuned to their habitats where the intensity and the wavelength of lights are changed depending on its water-depth. To study the detailed molecular characteristics of GPCR architecture and to understand the fishery light-sensing system, genes encoding rod opsins were isolated from fishes living under different photic environments. Full-length rod opsin genes were obtained by combination of PCR amplification and DNA walking strategy of genomic DNA isolated from olive flounder, P. olivaceus, Japanese eel, A. japonica, and Common carp C. carpio. Deduced amino acid sequences showed a typical feature of rod opsins including the sites for Schiffs base formation (Lys296) and its counter ion (Glu113), disulfide formation (Cys110 and Cys187), and palmitoylation (Cys322 and Cys323) although Cys322 is replaced by Phe in Japanese eel. Comparison of opsins by amino acid sequence alignment indicated the closest similarity between P. olivaceus and H. hippoglossus (94%), A. japonica and A. anguilla (98%), and C. carpio and C. auratus (95%), respectively.

• 한국동물학회지
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• 제3권1호
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• pp.1-4
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• 1960

The test group and control group, which were grouped with the same weight of five frogs (Rana nigromaculata) respectively, were adapted to light for two hours. Then the anterior lymph heart of the test group were injected with 0.5 cc of 0.1% acetyl choline and 0.5cc of Vitamin B12 (50mc gm/cc). After the frogs of this group were dark-adapted for 90 minutes, their heads were cut off under the dim red light and then their retina removed from eye-balls were extracted with 2% digitonin solution for 20 hours at $0^{\circ}C$. The results of the comparison of these two groups whose optical densities were measured before and after the illumination areas follows : (1) The group which had been injected with 0.5cc of 0.1% acetyl choline solution had the protomotive action on the regeneration of rhodopsin in comparison with the control group. (2) The group which had been injected with 25 mc gm of Vitamin B12 and 0.5cc of 0.1% acetyl choline solution had the controlling action on the regeneration of rhodopsin in comparison with the control group.

• 한국광과학회:학술대회논문집
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• 한국광과학회 2005년도 제12회 학술대회 논문초록
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• pp.48-48
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• 2005

• 통합자연과학논문집
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• 제8권1호
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• pp.75-79
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• 2015

Thromboxane A2 receptors (TXA2-R) are the G protein coupled receptors localized on cell membranes and intracellular structures and play pathophysiological role in various thrombosis/hemostasis, modulation of the immune response, acute myocardial infarction, inflammatory lung disease, hypertension and nephrotic disease. TXA2 receptor antagonists have been evaluated as potential therapeutic agents for asthma, thrombosis and hypertension. The role of TXA2 in wide spectrum of diseases makes this as an important drug target. Hence in the present study, homology modeling of TXA2 receptor was performed using the crystal structure of squid rhodopsin and night blindness causing G90D rhodopsin. 20 models were generated using single and multiple templates based approaches and the best model was selected based on the validation result. We found that multiple template based approach have given better accuracy. The generated structures can be used in future for further binding site and docking analysis.

• Applied Microscopy
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• 제50권
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• pp.11.1-11.3
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• 2020

The human turbinate-derived mesenchymal stem cells (hTMSCs), which were DiI-labeled and transplanted into the subretinal space in degenerating mouse retina, were observed in retinal vertical sections processed for rhodopsin (a marker for rod photoreceptor) by confocal microscope with differential interference contrast (DIC) filters. The images clearly demonstrated that DiI-labeled hTMSCs have rhodopsin-immunoreactive appendages, indicating differentiation of transplanted hTMSC into rod photoreceptor. Conclusively, the finding suggests therapeutic potential of hTMSCs in retinal degeneration.

• Journal of Photoscience
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• 제9권2호
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• pp.534-536
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• 2002

A halophilic archaeon, Halobacterium salinarum, exhibits phototactic behaviors, by which the organism is guided to red-orange light and evades shorter wavelengths of light. The phototaxis is mediated by two retinal proteins, sensory rhodopsin I and II (SRI and SRII), whose structures are analogous to the cognate protein bacteriorhodopsin, a light-driven proton pump. SRI mediates both attractant and repellent swimming behaviors to orange light and near- UV light, respectively. The two different signaling through the single photoreceptor have been ascribed to the presence of two active structures of SRI (S$\_$373/ and P$\_$520), which are produced upon orange light illumination of SRI and upon subsequent near-UV illumination of S$\_$373/, respectively. In the present study, we have measured the difference FTIR spectra of S$\_$373/ and P$\_$520/ states. In P$\_$520/, the isomeric structure of the chromophore is assignable to all-trans, and the Schiff base of the chromophore is protonated with concomitant deprotonation of Asp76, a combination which allows for the formation of a salt bridge between them. It was suggested that the way of interaction between the Schiff base and the counterion, which is different among SRI$\_$587/, S$\_$373/ and P$\_$520/ and which has been shown to drive the conformational changes in the cognate protein, bacteriorhodopsin, is the key to controlling conformational changes for the attractant and the repellent signaling by SRI.

• Nutrition Research and Practice
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• 제14권3호
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• pp.203-217
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• 2020

BACKGROUND/OBJECTIVE: Centella asiatica, also known as Gotu kola, is a tropical medicinal plant native to Madagascar, Southeast Asia, and South Africa. It is well known to have biological activities, including wound healing, anti-inflammatory, antidiabetic, cytotoxic, and antioxidant effects. The purpose of this study was to determine the efficacy of extracts of C. asiatica against age-related eye degeneration and to examine their physiological activities. MATERIALS/METHODS: To determine the effects of CA-HE50 (C. asiatica 50% EtOH extract) on retinal pigment cells, we assessed the cytotoxicity of CoCl₂ and oxidized-A2E in ARPE-19 cells and observed the protective effects of CA-HE50 against N-methyl-N-nitrosourea (MNU)-induced retinal damage in C57BL/6 mice. In particular, we measured factors related to apoptosis and anti-oxidation and the protein levels of rhodopsin/opsin. We also measured glucose uptake to characterize glucose metabolism, a major factor in cell protection. RESULTS: Induction of cytotoxicity with CoCl₂ and oxidized-A2E inhibited decreases in the viability of ARPE-19 cells when CA-HE50 was administered, and promoted glucose uptake under normal conditions (P < 0.05). In addition, CA-HE50 inhibited degeneration/apoptosis of the retina in the context of MNU-induced toxicity (P < 0.05). In particular, CA-HE50 at 200 mg/kg inhibited the cleavage of pro-caspase-3 and pro-poly (ADP-ribose)-polymerase and maintained the expressions of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 similar to normal control levels. Rhodopsin/opsin expression was maintained at a higher level than in normal controls. CONCLUSION: A series of experiments confirmed that CA-HE50 was effective for inhibiting or preventing age-related eye damage/degeneration. Based on these results, we believe it is worthwhile to develop drugs or functional foods related to age-related eye degeneration using CA-HE50.

• Animal cells and systems
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• 제9권3호
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• pp.139-144
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• 2005

The attractant (orange light) or repellent (white light) signal is transmitted from SRI (Sensory Rhodopsin I) via protein-protein interaction with its transducer Htrl (Halobacterial Transducer for Sensory Rhodopsin I) which in turn controls a cytoplasmic phospho-transfer pathway that modulates flagella motor switching in Halobacterium salinarum. Some mutations in both SRI and Htrl showed an unusual mutant phenotype called inverted signaling, in which the cell produces a repellent response to normally attractant light. Twelve mutations at the Glutamate 56 (E56) position in the second transmembrane helix of Htrl were introduced by site-specific random mutagenesis. Almost all E56 mutants showed orange-light inverted responses in pH and temperature-dependent manners except E56D and E56Y. Except for these two mutants, all mutants accelerated the $S_{373}$ decay compared to wild-type at $18^{\circ}C$. This supported that there is an interaction between SRI and the second transmembrane of Htrl. Also a structural model of Htrl based on the Tar crystal structure and the secondary structure prediction program proposed the E56 residue to be in the middle of the proton channel. The most important observation is that the E56 mutant provides the evidence that this residue is very sensitive for signal relay, which can be explained by the open and closed conformations of the channel (A and R conformations) in SRI, as was postulated by the unified conformational shuttling model for transport and signaling.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2008년도 International Meeting of the Microbiological Society of Korea
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• pp.165-165
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• 2008

• Journal of Photoscience
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• 제9권2호
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• pp.305-307
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• 2002

Spectroscopic titration of D 193N and D 193E mutants of pharaonis phoborhodopsin (ppR) were performed to evaluate the pK$_{a}$ of the Schiff base Asp 193 corresponds to Glu204 of bacteriorhodopsin (bR). The pK$_{a}$ of the Schiff base (SBH$^{+}$) of D193N was 10.1~10.0 (at XH$^{+}$) and 11.4~11.6 (at X) depending on the protonation state of a certain residue (designated by X) and independent on CI$^{[-10]}$ , while those of the wild-type and D193E were> 12. pK$_{a}$ of XH$^{+}$ were; 11.8~11.2 at the state of SB, 10.5 at SBH$^{+}$ state in the presence of CI$^{[-10]}$ , and 9.6 at SBH$^{+}$ without CI$^{[-10]}$ These imply the presence of a long-range interaction in the extracellular channel.r channel.