• 한국패류학회지
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• 제21권1호
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• pp.47-56
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• 2005

A series of radiotracer experiments were employed to quantitatively compare the biokinetics of uptake from the dissolved phase (influx rates), uptake from the various types of food source (assimilation efficiency), and loss (efflux) of Ag between Potamocorbula amurensis and Macoma balthica. Simultaneously, influx rates of dissolved Cd in both clams were determined to compare with those of Ag. Effects of salinity on influx rates were evaluated in these 2 euryhaline species, as were effects of clam size. Influx rate of Ag and Cd (${\mu}g g^{-1}$ [dry wt.] $d^{-1}$) increased linearly with metal concentrations. Influx rates of Ag in both clams were 3 to 4 times those of Cd. Absolute influx rates of the 2 metals were 4 to 5 times greater in P. amurensis than M. balthica, probably because of differences in biological attributes (i.e. clearance rate or gill surface area). As salinity was reduced from 20 to 2.5 psu, the influx rate of Cd in P. amurensis increased 4-fold and that of Ag increased 6-fold, consistent with expected changes in speciation. Weight-specific metal influx rates (${\mu}g g^{-1}$ [dry wt.] $d^{-1}$) were negatively correlated with the tissue dry weight of the clams, but most rate constants determining physiological turnover of assimilated metals were not affected by clam size.

• IMMUNE NETWORK
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• 제12권6호
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• pp.284-290
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• 2012

Innate immune cells sense and respond to the cytoplasmic infection of bacterial pathogens through NLRP3, NLRC4 or AIM2 inflammasome depending on the unique molecular pattern of invading pathogens. The infection of flagellin- or type III secretion system (T3SS)-containing Gram-negative bacteria such as Salmonella enterica serovar Typhimurium (S. typhimurium) or Pseudomonas aeruginosa (P. aeruginosa) triggers NLRC4-dependent caspase-1 activation leading to the secretion of proinflammatory cytokines such as interleukin-1-beta (IL-$1{\beta}$) and IL-18. Previous studies have shown that apoptosis-associated speck-like protein containing a CARD (ASC) is also required for Salmonella-induced caspase-1 activation, but it is still unclear how ASC contributes to the activation of NLRC4 inflammasome in response to S. typhimurium infection. In this study, we demonstrate that S. typhimurium triggers the formation of ASC oligomer in a potassium depletion-independent manner as determined by in vitro crosslinking and in situ fluorescence imaging. Remarkably, inhibition of potassium efflux failed to block Salmonella-promoted caspase-1 activation and macrophage cell death. These results collectively suggest that ASC is substantially oligomerized to facilitate the activation of caspase-1 in response to S. typhimurium infection. Contrary to NLRP3 inflammasome, intracellular potassium depletion is not critical for NLRC4 inflammasome signaling by S. typhimurium.

• 한국발생생물학회지:발생과생식
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• 제7권2호
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• pp.81-88
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• 2003

정자의 운동개시는 수정시에 정자와 난자가 만나기 위한 전제조건이다. 동물의 정자는 CAMP와Ca2'의 조절기구에 의해서 정자의 운동개시가 일어난다. 정자운동 활성 및 개시를 위한 세포 신호전달기구는 멍게류와 연어과 어류에서 많은 연구가 이루어져 왔다. 멍게류의 경우, 난에서 분비되는 정자 활성 및 유인물질(sperm-activating and -attracting factor)은 정자 활성 및 난으로의 유인을 위하여 외부의 $Ca^{2+}$을 요구한다. 한편 연어과 어류의 정자에서는 Cyclic AMP 의존형의 단백질 인산화가 정자 운동개시 기구에 관여한다. 방정된 정자 주위의 $K^{+}$ 농도의 감소는 특정한 $K^{+}$ channel 및 dihydropyridine 감수성의 L-/T- type $Ca^{2+}$ channel을 통한 $K^{+}$ 유출과 $Ca^{2+}$ 유입에 의해 세포막의 과분극과 세포내 $Ca^{2+}$ 이온의 농도증가를 가져온다. 세포막의 과분극에 의해서 합성된 cyclic AMP는 정자 운동개시의 주요기구인 cyclic AMP의존형의 단백질 인산화를 유도한다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.174-174
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• 2017

To cope with phosphate (Pi) deficient stress, plants modulate various physiological and developmental processes, such as gene expression, Pi uptake and translocation, and root architecture changes. Here, we report the identification and characterization of novel activation-tagged mutant involved in Pi starvation signaling in Arabidopsis. The hpd (${\underline{h}ypersensitive}$ to ${\underline{P}i}$ $ {\underline{d}eficiency}$) mutant exhibits enhanced phosphate uptake and altered root architectural change under Pi starvation compared to wild type. Expression analysis of auxin-responsive DR5::GUS reporter gene in hpd mutant indicated that auxin translocation in roots under Pi starvation are suppressed in hpd mutant plants. Impaired auxin translocation in roots of hpd mutant was attributable to abnormal root architecture changes in Pi starvation conditions. Our results indicated that abnormal auxin translocation in hpd mutant might be due to mis-regulation of auxin efflux carrier proteins, PIN-FORMED (PIN) 1, and 2 under Pi starvation conditions. Not only expression levels but also expression domains of PIN proteins were altered in hpd mutant in response to Pi starvation. Molecular genetic analysis of hpd mutant revealed that the mutant phenotype is caused by the lesion in ENHANCED SILENCING PHENOTYPE4 (ESP4) gene whose function is proposed in mRNA 3'-end processing. The results suggest that mRNA processing plays crucial roles in Pi homeostasis as well as developmental reprograming in response to Pi deprivation in Arabidopsis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권3호
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• pp.991-996
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• 2015

Side population (SP) cells have stem cell-like properties with a capacity for self-renewal and are resistant to chemotherapy and radiotherapy. Therefore the presence of SP cells in human breast cancer probably has prognostic value. Objective: To investigate the characteristics of SP cells and identify the relationship between the SP cells levels and clinico-pathological parameters of the breast tumor and disease-free survival (DFS) in breast cancer patients. Materials and Methods: A total of 122 eligible breast cancer patients were consecutively recruited from January 1, 2006 to December 31, 2007 at Yunnan Tumor Hospital. All eligible subjects received conventional treatment and were followed up for seven years. Predictors of recurrence and/or metastasis and DFS were analyzed using Cox regression analysis. Human breast cancer cells were also obtained from fresh human breast cancer tissue and cultured by the nucleic acid dye Hoechst33342 with Verapami. Flow cytometry (FCM) was employed to isolate the cells of SP and non-SP types. Results: In this study, SP cells were identified using flow cytometric analysis with Hoechst 33342 dye efflux. Adjusted for age, tumor size, lymph nodal status, histological grade, the Cox model showed a higher risk of recurrence and/or metastasis positively associated with the SP cell level (1.75, 1.02-2.98), as well as with axillary lymph node metastasis (2.99, 1.76-5.09), pathology invasiveness type (1.7, 1.14-2.55), and tumor volume doubling time (TVDT) (1.54, 1.01-2.36). Conclusions: The SP cell level is independently associated with tumor progression and clinical outcome after controlling for other pathological factors. The axillary lymph node status, TVDT and the status of non-invasive or invasive tumor independently predict the prognosis of breast cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3213-3217
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• 2013

Background: P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter which plays an important role in pharmacokinetics. The current preliminary study was designed to determine associations between a germ-line polymorphism in the MDR1 gene with differentiated thyroid carcinoma (DTC). Materials and Methods: In the current case-control study, 60 differentiated thyroid cancers (DTC)- 45 papillary TC (PTC), 9 follicular TC(FTC) and 6 well-differentiated tumors of uncertain malignant potential (WDT-UMP) were examined. Results were compared to a healthy control group (n=58) from the same population. Genomic DNA was extracted from peripheral blood with EDTA and the target gene was genotyped by real-time PCR. Results: Carriers of the variant allele of MDR1 exon 26 polymorphism were at 2.8-fold higher risk of DTC than the control group (odds ratio [OR]: 0.3805, 95% confidence interval [Cl]: 0.1597-0.9065 (p> 0.046). Conclusions: Presented results suggest that the MDR1 3435TT genotype might influence risk of development of DTC and that the CC genotype might be linked to a poor prognosis. Large-scale studies are now needed to validate this association.

• International Journal of Oral Biology
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• 제34권2호
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• pp.97-103
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• 2009

L-trans-pyrrolidine-2,4-dicarboxylate (PDC) is a potent inhibitor of glutamate transporters. In our current study, we investigated whether the neuronal death induced by PDC involves mechanisms other than excitotoxicity in mixed mouse cortical cultures. Cortical cultures at 13-14 days in vitro were used and cell death was assessed by measuring the lactate dehydrogenase efflux into bathing media. Glutamate and PDC both induced neuronal death in a concentration-dependent manner but the neurotoxic effects of glutamate were found to be more potent than those of PDC. Treatment with 10, 100 and 200 ${\mu}$M PDC equally potentiated 50 ${\mu}$M glutamate-induced neuronal death. The neuronal death induced by 75 ${\mu}$M glutamate was almost abolished by treatment with the NMDA antagonists, MK-801 and AP-5, but was unaffected by NBQX (an AMPA antagonist), trolox (antioxidant), BDNF or ZVAD-FMK (a pan-caspase inhibitor). However, the neuronal death induced by 200 ${\mu}$M PDC was partially but significantly attenuated by single treatments with MK-801, AP-5, trolox, BDNF or ZVAD-FMK but not NBQX. Combined treatments with MK-801 plus trolox, MK-801 plus ZVAD-FMK or MK-801 plus BDNF almost abolished neuronal death, whereas combined treatments with trolox plus ZVADFMK, trolox plus BDNF or ZVAD-FMK plus BDNF did not enhance the inhibitory action of any single treatment with these drugs. These results demonstrate that the neuronal death induced by PDC involves not only in the excitotoxicity induced by the accumulation of glutamate but also the oxidative stress induced by free radical generation. This suggests that apoptotic neuronal death plays a role in PDCinduced oxidative neuronal injury.

• Journal of Korean Neurosurgical Society
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• 제30권9호
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• pp.1059-1064
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• 2001

Objective : 6R-Tetrahydrobiopterin(BH4) is a cofactor for the aromatic amino acid hydroxylases which is essential for the biosynthesis of catecholamines and serotonin. It also acts as a cofactor for nitric oxide synthase, and stimulates the release of some neurotransmitters such as dopamine, serotonin, acetylcholine and glutamate. Recently, it has been reported that BH4 could induce cellular proliferation and enhance neuronal survival. This study was performed to investigate the antioxidative effect of BH4 on the various oxidative insults in mouse cerebral cortical cell cultures. Methods : Iron ion(FeCl2), zinc ion(ZnCl2), sodium nitroprusside(SNP) and buthionine sulfoximine(BSO, a glutathione depletor) were used as oxidants. Cell death was assessed by measurement of lactate dehydrogenase efflux to bathing media at the end of exposure. Result : All 4 oxidants induced neuronal cell death associated with cell body swelling, which was markedly inhibited by trolox($100{\mu}M$), a vitamin E analog. BH4($10-100{\mu}M$) markedly inhibited the neuronal cell death induced by all 4 oxidants($20{\mu}M\;Cu^{2+}$, $20{\mu}M\;Zn^{2+}$, $1{\mu}M$ SNP or 1mM BSO). However, BH4 failed to inhibit the neuronal cell death induced by 24hr exposure to $20{\mu}M$ NMDA. Conculsion : These results suggest that BH4 has antioxidative action independently of any actions of enzyme cofactor.

• Nutrition Research and Practice
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• 제6권5호
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• pp.414-420
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• 2012

Forty guinea pigs were divided into four groups and fed 0.04% cholesterol based control diet, plus 0.05% simvastatin, and statin plus 0.1% CoQ10 or 10% Ardisia Japonica Blume (AJB) leave powder for 4 weeks. Plasma total cholesterol levels decreased significantly in all groups fed the statin-containing diet compared with that in guinea pigs fed the control diet (P < 0.01). Plasma and liver triglycerides decreased significantly in the statin plus CoQ10 group compared with those in the control (both P < 0.05). Maximum platelet aggregation was significantly higher in the statin plus CoQ10 group than that in the other groups (P < 0.05). Na-K ATPase activity increased in the statin group and decreased in the statin plus CoQ10 group (P < 0.01). Na-K co-transport and Na passive transport decreased significantly in the control group compared with those in the other groups (both P < 0.05). Intracellular Na was highest in the statin group and lowest in the statin plus CoQ10 group and was correlated with Na-K ATPase activity. Thiobarbituric acid reactive substance production in platelet-rich plasma and liver tended to decrease in the statin plus CoQ10 group compared with those in the other groups. Plasma glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase increased significantly in the statin group compared with those in the control (P < 0.05). These result suggest that antioxidant rich AJB did not have positive effects on cardiovascular disease parameters. The statin plus CoQ10 seemed to decrease cholesterol more efficiently than that of statin alone.

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.43-47
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• 2008

The nickel and cobalt resistance of Cupriavidus metallidurans CH34 is mediated by the CnrCBA efflux pump encoded by the cnrYHXCBAT metal resistance determinant. The products of the three genes cnrYXH transcriptionally regulate expression of cnr. CnrY and CnrX are membrane-bound proteins, probably functioning as anti-sigma factors, whereas CnrH is a cnr-specific extracytoplasmic functions (ECF) sigma factor. The periplasmic domain of CnrX (residues 29-148) was cloned as a N-terminal His-tagged protein, expressed in Escherichia coli, and purified using affinity chromatography and gel filtration. The molecular mass was estimated to be about 13.6kDa by size exclusion chromatography, corresponding to a monomer. The tetragonal bipyramid crystals were obtained by mixing an equal volume of protein in 50mM Tris-HCl, pH 7.5, 1% glycerol, 100mM NaCl, 1mM DTT, and the reservoir solution of 15% w/v PEG 2000, 100mM lithium chloride at 277K in 2-4 days using hanging drop vapor diffusion. The protein concentration was 24mg/ml. The crystal that diffracted to $2.42{\AA}$ resolution belongs to space group $P4_1\;or\;P4_3$ with unit cell parameters of $a=b=32.14{\AA},\;c=195.31{\AA},\;{\alpha}={\beta}={\gamma}=90^{\circ}$, with one molecule of CnrX in the asymmetric unit.