• 한국미생물·생명공학회지
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• 제24권4호
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• pp.485-492
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• 1996

myo-Inositol, a growth factor for Saccharomyces cerevisiae (S. cerevisiae), has been known to be incorporated into phosphatidylinositol (PI), which is a kind of phospholipid in the cell membrane, by a membrane-associated PI-synthesizing enzyme. The deficiency of myo-inositol in S. cerevisiae adversely affected the membrane structure and function. On the basis of biochemical functions of myo-inositol, the effect of deficiency of myo-inositol on the aerobic glucose metabolism was investigated by measuring specific oxygen uptake rate (Q$_{O2}$) used as an indicator representing the respiratory capacity of S. cerevisiae in batch and continuous cultures. The respiratory capacity of aerobic glucose metabolism in S. cerevisiae was also monitored after glucose pulse-addition in a continuous culture (D=0.2, 1/hr), in which glucose was utilized through respiratory metabolism. The deficiency of myo-inositol was found to lead to both the decrease of the maximum specific oxygen uptake rate (Q$_{O2max}$) observed from the batch as well as in the continuous culture experiment and the decrease of the respiratory capacity of aerobic glucose metabolism of S. cerevisiae determined from the glucose pulse-addition experiment, in which the glucose flux into respiratory and fermen- tative metabolism was quantitatively analyzed.

• Nuclear Medicine and Molecular Imaging
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• 제41권2호
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• pp.118-131
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• 2007

Neurotransmitter imaging with radiopharmaceuticals plays major role for understanding of neurological and psychiatric disorders such as Parkinson's disease and depression. Radiopharmaceuticals for neurotransmitter imaging can be divided to dopamine transporter imaging radiopharmaceuticals and serotonin trnasporter imaging radiopharmaceuticals. Many kinds of new dopamine transporter imaging radiopharmcaeuticals has a tropane ring and they showed different biological properties according to the substituted functional group on tropane ring. After the first clinical trials with $[^{123}I]{\beta}-CIT$, alkyl chain substituent introduced to tropane ring amine to decrease time for imaging acquisition and to increase selectivity. From these results, $[^{123}I]PE2I$, [18F]FE-CNT, $[^{123}I]FP-CIT$ and $[^{18}F]FP-CIT$ were developed and they showed high uptake on the dopamine transporter rich regions and fast peak uptake equilibrium time within 4 hours after injection. $[^{11}C]McN$ 5652 was developed for serotonin trnasporter imaging but this compound showed slow kinetics and high background radioactivity. To overcome these problems, new diarylsulfide backbone derivatives such as ADAM, ODAM, AFM, and DASB were developed. In these candidates, $[^{11}C]AFM$ and $[^{11}C]DASB$ showed high binding affinity to serotonin transporter and fast in vivo kinetics. This paper gives an overview of current status on dopamine and serotonin transporter imaging radiopharmaceuitcals and the development of new lead compounds as potential radiopharmaceuticals by medicinal chemistry.

• 대한방사성의약품학회지
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• 제5권1호
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• pp.36-47
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• 2019

Hypoxia-inducible factor-1 ($HIF-1{\alpha}$) is a transcription factor activated in response to low oxygen level, and is highly expressed in many solid tumors. Moreover, $HIF-1{\alpha}$ is a representative biomarker of hypoxia and also helps to maintain cell homeostasis under hypoxic condition. Most solid tumors show hypoxia, which induces poor prognosis and resistance to conventional cancer therapies. Thus, early diagnosis of hypoxia with positron emission tomography (PET) radiotracer would be highly beneficial for management of malignant solid tumors with effective cancer therapy. YC-1 is a most promising candidate among several $HIF-1{\alpha}$ inhibitors. As an effort to develop a hypoxia imaging tool as a PET radiotracer, we designed and synthesized [$^{18}F$]DFYC based on potent derivative of YC-1 and performed preliminary in vitro cell uptake study. [$^{18}F$]DFYC showed a significant accumulation in SKBR-3 cells among other cancer cells, proving as a good lead to develop a hypoxic solid tumor such as breast cancer.

• Parasites, Hosts and Diseases
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• 제61권4호
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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.

• Mycobiology
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• 제45권2호
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• pp.73-83
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• 2017

The ability of dead cells of endophytic Drechslera hawaiiensis of Morus alba L. grown in heavy metals habitats for bioremoval of cadmium ($Cd^{2+}$), copper ($Cu^{2+}$), and lead ($Pb^{2+}$) in aqueous solution was evaluated under different conditions. Whereas the highest extent of $Cd^{2+}$ and $Cu^{2+}$ removal and uptake occurred at pH 8 as well as $Pb^{2+}$ occurred at neutral pH (6-7) after equilibrium time 10 min. Initial concentration 30 mg/L of $Cd^{+2}$ for 10 min contact time and 50 to 90 mg/L of $Pb^{2+}$ and $Cu^{2+}$ supported the highest biosorption after optimal contact time of 30 min achieved with biomass dose equal to 5 mg of dried died biomass of D. hawaiiensis. The maximum removal of $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$ equal to 100%, 100%, and 99.6% with uptake capacity estimated to be 0.28, 2.33, and 9.63 mg/g from real industrial wastewater, respectively were achieved within 3 hr contact time at pH 7.0, 7.0, and 6.0, respectively by using the dead biomass of D. hawaiiensis compared to 94.7%, 98%, and 99.26% removal with uptake equal to 0.264, 2.3, and 9.58 mg/g of $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$, respectively with the living cells of the strain under the same conditions. The biosorbent was analyzed by Fourier Transformer Infrared Spectroscopy (FT-IR) analysis to identify the various functional groups contributing in the sorption process. From FT-IR spectra analysis, hydroxyl and amides were the major functional groups contributed in biosorption process. It was concluded that endophytic D. hawaiiensis biomass can be used potentially as biosorbent for removing $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$ in aqueous solutions.

• 약학회지
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• 제40권2호
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• pp.218-224
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• 1996

This laboratory has recently reported the synthesis and in vitro antitumor activity of PT(II) complexes containing ethylenediamine and diphosphine. In view of the reports of others, cisplatin is toxic to the kidney since the kidney's vulnerability to PT(II) complexes may originate in its ability to accumulate and retain platinum to a greater degree than other organs. The in vitro cytotoxicity of these synthetic PT(II) complexes on the primary cultured proximal tubular cells of rabbit kidney and renal cortical cells of human kidney was investigated. Three endpoints for cytotoxicity tests were evaluated:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), $^3H$-thymidine uptake and the glucose consumption tests. The rank order of sensitivity exhibited $^3H$-thymidine uptake>MTT>glucose consumption test. The agents with diphosphine leaving group were significantly less cytotoxic than cisplatin. Moreover, 1,2-bis(diphenylphosphino)ethane (DPPE) exhibited less cytotoxicity than 1.3-bis (diphenylphosphino)propane (DPPP) against on rabbit and human cultured kidney cells. Based on these results, the decreased nephrotoxicity of these new complexes over cisplatin appeared to be partially attributable to a leaving group of DPPP and DPPE. This novel class of platinum compound represents a valuable lead in the development of a "third-generation" agent.

• Childhood Kidney Diseases
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• 제20권2호
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• pp.63-68
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• 2016

Purpose: Disruption of normal renal development can lead to congenital anomalies of the kidney and urinary tract, including renal hypodysplasia. We aimed to clarify whether small kidney size affects clinical manifestations in children with urinary tract infection (UTI). Methods: One hundred fifty-four patients who had their first symptomatic UTI between January 2014 and June 2015 were enrolled in this study. Differences in kidney size were estimated based on percent uptake of $^{99m}Tc-$ dimercaptosuccinic acid (DMSA) in scintigraphy. The patients who showed more than 10% difference in kidney size on DMSA scintigraphy with none or minimal cortical defects were included in group A. (group A, n=17). Laboratory, clinical, and imaging results were compared with those of the other patients (group B, n=137). Results: Group A had a relatively higher incidence of vesicoureteral reflux than group B (44% vs 20%, P<0.05). The levels of plasma neutrophil gelatinase-associated lipocalin (NGAL) and serum C-reactive protein were significantly higher in group A (193 [64-337] vs 91 [59-211] ng/mL and 4.1 [0.5-11.9] vs 2.1 [0.7-5.3] ng/mL, respectively; all P <0.05). Linear regression analysis revealed that plasma NGAL level strongly correlated with the difference in renal uptake in DMSA scintigraphy in group A ($R^2=0.505$). Conclusion: The difference in kidney size could influence the clinical course and severity of pediatric UTI.

• Biomolecules & Therapeutics
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• 제29권5호
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• pp.498-505
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• 2021

Amyotrophic lateral sclerosis (ALS) is a lethal neurological disorder characterized by the deterioration of motor neurons. The aim of this study was to investigate alteration of cationic amino acid transporter (CAT-1) activity in the transport of lysine and the pretreatment effect of lysine on pro-inflammatory states in an amyotrophic lateral sclerosis cell line. The mRNA expression of cationic amino acid transporter 1 was lower in NSC-34/hSOD1^G93A (MT) than the control cell line (WT), lysine transport is mediated by CAT-1 in NSC-34 cell lines. The uptake of [³H]L-lysine was Na⁺-independent, voltage-sensitive, and strongly inhibited by inhibitors and substrates of cationic amino acid transporter 1 (system y⁺). The transport process involved two saturable processes in both cell lines. In the MT cell line, at a high-affinity site, the affinity was 9.4-fold higher and capacity 24-fold lower than that in the WT; at a low-affinity site, the capacity was 2.3-fold lower than that in the WT cell line. Donepezil and verapamil competitively inhibited [³H]L-lysine uptake in the NSC-34 cell lines. Pretreatment with pro-inflammatory cytokines decreased the uptake of [³H]L-lysine and mRNA expression levels in both cell lines; however, the addition of L-lysine restored the transport activity in the MT cell lines. L-Lysine exhibited neuroprotective effects against pro-inflammatory states in the ALS disease model cell lines. In conclusion, studying the alteration in the expression of transporters and characteristics of lysine transport in ALS can lead to the development of new therapies for neurodegenerative diseases.

• 미생물학회지
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• 제30권4호
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• pp.310-315
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• 1992

수용액으로부터 $Pb^{2+}$ 의 흡수와 분리를 Staphylococcus epidermidis 를 이용하여 조사하였다. 흡수된 $Pb^{2+}$의 양을 초기 $Pb^{2+}$ 의 양에 대한 비율로 나타낸 것을 흡수율이라고 정의할 경우, 세균체의 농도가 높을수록 흡수율은 증가하였으며 세균체 단위 중량당 흡수율은 감소하였다. $Pb^{2+}$ 의 흡수율은 수용액의 pH 가 상승함에 따라 점차 증가하다가 최고치를 나타낸 후 감소하는 경향을 보였으며 $Pb^{2+}$ 의 농도가 증가할수록 흡수율의 최고치는 더 낮은 pH 에서 나타났다. HCI 과 EDTA 는 효과적인 탈락체로 작용하였으며 흡수와 탈착 cycle 의 횟수에 따른 세균체의 $Pb^{2+}$에 대한 흡수 능력에는 거의 변화가 없었다.$Pb^{2+}$ 이 다른 중금속 이온과 함께 혼재할 경우 세균내의 결합위치에 대한 경쟁적인 흡수로 인하여 $Pb^{2+}$ 의 흡수율이 변화하였으며, 공존하는 중금속 이온의 이온 반경이 작을수록$Pb^{2+}$ 의 흡수율이 더 크게 감소하였다.

• 한국미생물·생명공학회지
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• 제20권6호
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• pp.693-698
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• 1992

공장 폐수를 비롯한 중금속 오염 환경으로부터 효율적인 중금속 제거를 위해 생물학적 오염제거에 관한 연구가 많이 이루어지고 있다. 본 실험에서는 항생제 내성 유전자를 많이 가지고 있는 것으로 알려진 Serratia marcescens를 대상으로 이 균주가 중금속들에 대해 어떤 영향을 보이는지 조사하였다. 그 결과 lead, iron, magnesium, manganese 등의 처리군에서 24시간내에 1,000ppm 이상의 고농도 처리군에서 최소억제성장농도(MIC)를 나타냈으며, cadmium에서는 600ppm 처리군에서, 구리는 800ppm의 처리군에서 MIC를 보였으며, 아연 처리군에서는 800ppm에서 MIC를 나타냈다. 또한 48시간 배양에 따른 MIC 비교 결과, 중금속의 고농도 처리군에서 매우 긴 적응기를 갖는 것으로 확인하였다. 15가지의 항생체를 대상으로 저항성을 조사한 결과, ampicillin, tetracycline, cefamandole, cephalothin에서 저항성을 보엿으며 다른 S. marcescens 균주들에 비해 chloramphenicol에 대한 특이한 민감성을 보였다. 카드뮴과 납을 대상으로 중금속의 세포내 흡수를 조사한 결과 16.59%와 35.38%의 중금속이 세포내로 흡수되었음을 확인하였다.