• Journal of Ginseng Research
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• v.25 no.2
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• pp.74-81
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• 2001

The effect of Korean Ginseng saponins (total saponin, PD saponin and PT saponin) on the serotonin type 3 receptor, which is known to be involved in nausea and vomiting following anticancer chemotherapy or the general anesthesia, was investigated. after in vitro transcribed recombinant serotonin type 3 receptor in the Xenopus laevis oocyte, classic two electrodes voltage clamp technique was used. All of ginseng saponins inhibited the response of the agonist, serotonin, on the serotonin type 3 receptor in a dose-dependent manner. PT saponin showed to have the inhibitory effect more than 2 times as potent as PD saponin. Total saponin shifted the serotonin dose response plot to the right (EC$\_$50/, 0.70$\pm$0.17 $\mu$M into 3.57$\pm$1.42 $\mu$M, and Hill coefficient, 2.14$\pm$0.60 into 1.52$\pm$1.00). Ginseng saponin did not change the reversal potential (∼0 mV) of serotonin type 3 receptor. These results suggest that Korean ginseng saponin may have the inhibitory effect on serotonin type 3 receptor.

• Animal cells and systems
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• v.2 no.4
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• pp.529-538
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• 1998

In order to analyze the intracellu1ar localization of specific RNA components of ribonucleoproteins (RNP) in Xenopus oocytes, a modified protocol of whole-mount in situ Hybridization is presented in this paper, Mitochondria specific 12S rRNA probe was used to detect the amplification and distribution of mitochondria in various stages of the oocyte life cycle, and the results were found to be consistent with previously known distribution of mitochondria. The results with other specific probes (U1 and U3 small nuclear RNAs, and 5S RNA) also indicate that this procedure is generally effective in localizing RNAs in RNP complexes even inside organelles. In addition, the RNA component of RNase MRP, the RNP with endoribo-nuclease activity, localize to the nucleus in various stages of the oocyte life cycle. Some of MRP RNA, however, were found to be localized to the special population of mitochondria near the nucleus, especially in the active stage of mitochondrial amplification. It suggests dual localization of RNase MRP in the nucleus and mitochondria, which is consistent with the proposed roles of RNase MRP in mitochondrial DNA replication and in rRNA processing in the nucleolus.

• Archives of Pharmacal Research
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• v.18 no.1
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• pp.12-17
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• 1995

It is essential to clone the preptide transporter in order to obtain better understanding of its molecular structure, regulation, and substrate specificity. Characteristics of an endogenous peptide transporter in oocytes were studied along with expression of an exogenous protor/peptide cotransporter from rabbit intestine. And further efforts toward cloning the transporter were performed. The presence of an endogenous peptide transporter was detected in Xenopus laevis oocytes by measuring the uptake of $0.25/{mu}M(10{\;}{\mu}Ci/ml)[^3H]$-glycylsarcosine (Gly-Sar) at pH 5.5 with or without inhibitors. Yptake of Gly-Sae in oocytes was significantly inhibited by $25{\mu}M$ glycine nd sarcosine. This result suggests that a selective transporter is involved in the endogneous uptake of dipeptides. Collagenase treatment of oocytes used to strip oocytes from ovarian follicles did not affect the Gly-Sar uptake. Changing pH from 5.5 to 7.5 did not affect the Gly-Sae uptake significantly, suggesting no depedence of the endogenous transporter on a transmembrane proton gradient. An exogenous $H^+/pep-tide$ contransported was expressed after microinjection of polyadenylated messenger ribonucleic acid $[poly(A)^+ -mRNA]$ obtained from rabbit small intestine. The Gly-Sar uptake in mRNA-injected oocytes was 9 times thigher than that in water-injected oocyltes. Thus, frog occytes can be utilized fro expression cloning of the genes encoding intestinal $H^+$peptide contransporters. Size fractionation of mRNA was successfully obtained using this technique.

• Journal of Applied Biological Chemistry
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• v.53 no.4
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• pp.189-194
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• 2010

We confirmed the hypo-osmotic shock strengths and duration, different type of vectors, and subcelluar localization to identify the optimum analysis condition of plant aquaporin activity in Xenopus ooctye using Arabidopsis thaliana AtPIP2-1 gene. Six minutes and 1/5ND buffer hypoosmotic shock treatment was the best condition to show the maximum swelling of Xenopus oocytes where AtPIP2-1 was expressed using pcDNA3.1 vector. AtPIP2-1 protein was expressed more efficiently in pGEMHE vector which has 5' and 3' UTR (untranslation region) of Xenopus ${\beta}$-GLOBIN gene in multiple cloning site than in pcDNA3.1 vector. Also green fluorescence of GFP fused to AtPIP2-1 was detected onto oocyte plasmamembrane where is the proper subcellular localization target of AtPIP2-1.

• Parasites, Hosts and Diseases
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• v.61 no.4
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• pp.428-438
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• 2023

Clonorchis sinensis is commonly found in East Asian countries. Clonorchiasis is prevalent in these countries and can lead to various clinical symptoms. In this study, we used overlap extension polymerase chain reaction (PCR) and the Xenopus laevis oocyte expression system to isolate a cDNA encoding the choline transporter of C. sinensis (CsChT). We subsequently characterized recombinant CsChT. Expression of CsChT in X. laevis oocytes enabled efficient transport of radiolabeled choline, with no detectable uptake of arginine, α-ketoglutarate, p-aminohippurate, taurocholate, and estrone sulfate. Influx and efflux experiments showed that CsChT-mediated choline uptake was time- and sodium-dependent, with no exchange properties. Concentration-dependent analyses of revealed saturable kinetics consistent with the Michaelis-Menten equation, while nonlinear regression analyses revealed a Km value of 8.3 µM and a Vmax of 61.0 pmol/oocyte/h. These findings contribute to widen our understanding of CsChT transport properties and the cascade of choline metabolisms within C. sinensis.

• Proceedings of the Ginseng society Conference
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• 2003.12a
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• pp.30-31
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• 2003

• Proceedings of the Korean Biophysical Society Conference
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• 1999.06a
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• pp.57-57
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• 1999

It is well known that rapidly activating delayed rectifier $K^{＋}$ channels ( $I_{Kr}$ ) playa role in repolarisation in mammalian hearts. Recently, human ether-a- go- go related gene (HERG) channels was shown to be a molecular equivalent to $I_{Kr}$ . We have investigated the permeation of various external cations on $I_{Kr}$ in mammalian hearts and on HERG channels expressed in Xenopus laevis oocytes.(omitted)

• Archives of Pharmacal Research
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• v.28 no.4
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• pp.413-420
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• 2005

We previously demonstrated the ability of ginseng saponins (active ingredients of Panax ginseng) to enhance $Ca^{2+}$-activated $Cl^{-}$ current. The mechanism for this ginseng saponin-induced enhancement was proposed to be the release of $Ca^{2+}$ from $IP_{3}-sensitive$ intracellular stores through the activation of PTX-insensitive $G\alpha_{q/11}$ proteins and PLC pathway. Recent studies have shown that calmodulin (CaM) regulates $IP_{3}$ receptor-mediated $Ca^{2+}$ release in both $Ca^{2+}-dependent$ and -independent manner. In the present study, we have investigated the effects of CaM on ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current responses in Xenopus oocytes. Intraoocyte injection of CaM inhibited ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement, whereas co-injection of calmidazolium, a CaM antagonist, with CaM blocked CaM action. The inhibitory effect of CaM on ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement was dose- and time-dependent, with an $IC_{50} of 14.9\pm3.5 {\mu}M$. The inhibitory effect of CaM on saponin's activity was maximal after 6 h of intraoocyte injection of CaM, and after 48 h the activity of saponin recovered to control level. The half-recovery time was calculated to be $16.7\pm4.3 h$. Intraoocyte injection of CaM inhibited $Ca^{2+}$-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement and also attenuated $IP_{3}$-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement. $Ca^{2+}$/CaM kinase II inhibitor did not inhibit CaM-caused attenuation of ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement. These results suggest that CaM regulates ginseng saponin effect on $Ca^{2+}$-activated $Cl^{-}$ current enhancement via $Ca^{2+}$-independent manner.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.775-781
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• 2002

The T-type amino acid transporter 1 (TATI) is a Na$^{+}$-independent amino acid transporter which selectively trans- ports aromatic amino acids subserving the amino acid transport system T. To understand the transport properties of aromatic amino acids by human TAT1 (hTATl ), we have examined the hTATl -mediated aromatic amino acid transports using a Xenopus laeuis oocyte expression system. When expressed in Xenopin laeuis oocytes, hTATl induced L- [$^{14}$ C]tryptophan transport which was not dependent on Na$^{+}$ or Cl$^{[-10]}$ in the medium. Uptake was time-dependent and exhibited a linear dependence on incubation time up to 30 min. The L- ($^{14}$ C)tryptophan uptake was highly inhibited by L-isomers of tryptophan, tyrosine and phenylalanine, whereas other L-amino acids did not inhibit hTATl -mediated L- ($^{14}$ C)tryptophan uptake. The hTATl induced the relatively low-affinity transport of aromatic amino acids such as L- ($^{14}$ C)tryptophan, L- ($^{14}$ C)tyrosine and L- ($^{14}$ C)phenylalanine (Km values: 450～750 $\mu$M), consistent with the properties of classical amino acid transport system T. The L- ($^{14}$ C)tryptophan uptake did not show any remarkable pH dependence within the pH range of 5.5 to 8.5. The time-dependent efflux of L- ($^{14}$ C)tryptophan was detected from the oocytes expressing hTATl, which was not affected by the presence or absence of L-tryptophan in the extracellular medium, indicating that hTATl-mediated transport is due to the facilitated diffusion. Expression of hTATl in Xenopu laevis oocytes induced the transport of tryptophan, tyrosine and phenylalanine, indicating that hTATl is a transporter subserving system T These results suggest that hTATl has essential roles in the absorption of aromatic amino acids from epithelial cells to the blood stream. Hecause hTATl is proposed to be crucial to the efficient absorption of aromatic amino acids from intestine and kidney, its defect such as blue diaper syndrome could be involved in the disruption of aromatic amino acid transport.ort.

• Molecules and Cells
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• v.21 no.1
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• pp.52-62
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• 2006

In previous reports we demonstrated that ginsenosides, active ingredients of Panax ginseng, affect some subsets of voltage-dependent $Ca^{2+}$ channels in neuronal cells expressed in Xenopus laevis oocytes. However, the major component(s) of ginseng that affect cloned $Ca^{2+}$ channel subtypes such as ${\alpha}_{1C}$(L)-, ${\alpha}_{1B}$(N)-, ${\alpha}_{1A}$(P/Q)-, ${\alpha}_{1E}$(R)- and ${\alpha}_{1G}$(T) have not been identified. Here, we used the two-microelectrode voltage clamp technique to characterize the effects of ginsenosides and ginsenoside metabolites on $Ba^{2+}$ currents ($I_{Ba}$) in Xenopus oocytes expressing five different $Ca^{2+}$ channel subtypes. Exposure to ginseng total saponins (GTS) induced voltage-dependent, dose-dependent and reversible inhibition of the five channel subtypes, with particularly strong inhibition of the ${\alpha}_{1G}$-type. Of the various ginsenosides, $Rb_1$, Rc, Re, Rf, $Rg_1$, $Rg_3$, and $Rh_2$, ginsenoside $Rg_3$ also inhibited all five channel subtypes and ginsenoside $Rh_2$ had most effect on the ${\alpha}_{1C}$- and ${\alpha}_{1E}$-type $Ca^{2+}$ channels. Compound K (CK), a protopanaxadiol ginsenoside metabolite, strongly inhibited only the ${\alpha}_{1G}$-type of $Ca^{2+}$ channel, whereas M4, a protopanaxatriol ginsenoside metabolite, had almost no effect on any of the channels. $Rg_3$, $Rh_2$, and CK shifted the steady-state activation curves but not the inactivation curves in the depolarizing direction in the ${\alpha}_{1B}$- and ${\alpha}_{1A}$-types. These results reveal that $Rg_3$, $Rh_2$ and CK are the major inhibitors of $Ca^{2+}$ channels in Panax ginseng, and that they show some $Ca^{2+}$ channel selectivity.