• 대한핵의학회지
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• 제22권1호
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• pp.77-81
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• 1988

Tumor localizing properties of $^{67}Ga$ citrate and $^{169}Yb$ citrate were studies with sarcoma 180 bearing mice. To compare precisely the accumulation of $^{67}Ga$ citrate and $^{169}Yb$ citrate in tumor tissue itself, $^{67}Ga$ and l63yb were administered simultaneously as a mixture of same chemical form of citrate. The yield of $^{169}Yb$ labeled citrated and the of radiopharmaceuticals purity was identified more than 90% by chromatography on silica gel plates. $^{67}Ga$ and $^{169}Yb$ were injected into mice and the mice were killed at 3, 24, and 48 hours following intraperitoneal injection of the radiopharmaceuticals. The retention value of $^{67}Ga$ and $^{169}Yb$ in tumor was similar but they differ from each other markedly in normal tissue distribution. $^{169}Yb$ citrate is cleared up from blood more rapidly than $^{67}Ga$ citrate, and a high tumor to blood ratio is achieved shortly after injection.

• Journal of Microbiology and Biotechnology
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• 제6권2호
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• pp.120-127
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• 1996

The characteristics of cell growth and poly-$\beta$-hydroxybutyrate biosynthesis of Alcaligenes latus ATCC 29713 were investigated. The PHB accumulation pattern of A. latus followed a growth-associated type where the cell growth and PHB accumulation were carried out simultaneously. Various intermediate compounds such as metabolites involved in the TCA cycle, amino acids, and saturated and unsaturated fatty acids were added to examine their effect on cell growth and PHB accumulation. Citrate, tyrosine, and palmitic acid showed the most significant increase both on cell growth and PHB accumulation. Maximum PHB concentrations were noticeably increased about 1.4 to 1.6 times higher than that of control, corresponding to 5.54, 6.45, and 6.45 g/l for citrate, tyrosine, and palmitic acid, respectively. The stimulatory effects of the supplemented metabolites were analyzed in terms of the increment of enzyme activities related to sugar catabolism and PHB biosynthesis.

• 한국환경농학회지
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• 제28권2호
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• pp.146-157
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• 2009

The influence of Pb-citrate complex formation on Pb uptake and the effect of Pb on organic acid exudation were investigated using four plant species, viz., sunflower (Helianthus annuus L), Indian mustard (Brassica juncea), canola (Brassica napus) and vetiver grass (Vetiveria zizanioides) under hydroponic conditions. Seedlings were exposed to different levels of Pb and Pb-citrate for 24 hrs and subsequently Pb distributions in plant shoot, root and hydroponic solution were measured. The dissolved organic carbon (DOC) concentration generally decreased as the concentration of Pb in the hydroponic solution increased. In contrast to DOC, the total organic acid concentrations exuded from Indian mustard roots significantly increased (424 to 6656 mg $kg^{-1}$) with increased Pb treatment, implying that exuding organic acids were involved in Pb accumulation in Indian mustard. The complexation of Pb with citrate enhanced Pb accumulation in the above ground portions. Lead concentration in Indian mustard increased from 2.05 mg $kg^{-1}$ to 6.42 mg $kg^{-1}$ when the concentration of citrate in solution increased from 0 to 50 mg $L^{-1}$. This result showed enhanced translocation of Pb from root to shoot with observation of transfer coefficient ($K_t$) increase from 2.03E-3 to 5.72E-3.

• The Korean Journal of Physiology and Pharmacology
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• 제13권4호
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• pp.273-279
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• 2009

The accumulation of ${\beta}$-amyloid (A${\beta}$) aggregates is a characteristic of Alzheimer's disease (AD). Furthermore, these aggregates have neurotoxic effects on cells, and thus, molecules that inhibit A${\beta}$ aggregate formation could be valuable therapeutics for AD. It is well known that aggregation of A${\beta}$ depends on its hydrophobicity, and thus, in order to increase the hydrophilicity of A${\beta}$, we considered using citrate, an anionic surfactant with three carboxylic acid groups. We hypothesized that citrate could reduce hydrophobicity and increase hydrophilicity of A${\beta}_{1-40}$ molecules via hydrophilic/electrostatic interactions. We found that citrate significantly inhibited A${\beta}_{1-40}$ aggregation and significantly protected SH-SY5Y cell line against A${\beta}_{1-40}$ aggregates-induced neurotoxicity. In details, we examined the effects of citrate on A${\beta}_{1-40}$ aggregation and on A${\beta}_{1-40}$ aggregates-induced cytotoxicity, cell viability, and apoptosis. Th-T assays showed that citrate significantly inhibited A${\beta}_{1-40}$ aggregation in a concentration-dependent manner (Th-T intensity: from 91.3% in 0.01 mM citrate to 82.1% in 1.0 mM citrate vs. 100.0% in A${\beta}_{1-40}$ alone). In cytotoxicity and viability assays, citrate reduced the toxicity of A${\beta}_{1-40}$ in a concentration-dependent manner, in which the cytotoxicity decreased from 107.5 to 102.3% as compared with A${\beta}_{1-40}$ aggregates alone treated cells (127.3%) and the cell viability increased from 84.6 to 93.8% as compared with the A${\beta}_{1-40}$ aggregates alone treated cells (65.3%). Furthermore, Hoechst 33342 staining showed that citrate (1.0 mM) suppressed A${\beta}_{1-40}$ aggregates-induced apoptosis in the cells. This study suggests that citrate can inhibit A${\beta}_{1-40}$ aggregation and protect neurons from the apoptotic effects of A${\beta}_{1-40}$ aggregates. Accordingly, our findings suggest that citrate administration should be viewed as a novel neuroprotective strategy for AD.

• Journal of Microbiology and Biotechnology
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• 제6권6호
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• pp.425-431
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• 1996

The enzymatic characteristics of Alcaligenes latus were investigated by measuring the variations of various enzyme activities related to biosynthesis and degradation of poly-${\beta}$-hydroxybutyrate (PHB) during cultivation. All PHB biosynthetic enzymes, ${\beta}$-ketothiolase, acetoacetyl-CoA reductase, and PHB synthase, were activated gradually at the PHB accumulation stage, and the PHB synthase showed the highest value among three enzymes. This indicates that the rate of PHB biosynthesis is mainly controlled by either ${\beta}$-ketothiolase or acetoacetyl-CoA reductase rather than PHB synthase. The enzymatic activities related to the degradation of PHB were also measured, and the degradation of PHB was controlled by the activity of PHB depolymerase. The effect of supplements of metabolic regulators, citrate and tyrosine, was also investigated, and the activity of glucose-6-phosphate dehydrogenase was increased by metabolic regulators, especially by tyrosine. The activities of ${\beta}$-ketothiolase and acetoacetyl-CoA reductase were also activated by citrate and tyrosine, while the activity of PHB depolymerase was depressed. The increased rate and yield of PHB biosynthesis by metabolic regulators may be due to the increment of acetyl-CoA concentration either by the repression of the TCA cycle by citrate through product inhibition or by the activation of sucrose metabolism by the supplemented tyrosine.

• Molecules and Cells
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• 제43권11호
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• pp.964-973
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• 2020

Recent studies have highlighted that early enhancement of the glycolytic pathway is a mode of maintaining the proinflammatory status of immune cells. Thiamine, a wellknown co-activator of pyruvate dehydrogenase complex, a gatekeeping enzyme, shifts energy utilization of glucose from glycolysis to oxidative phosphorylation. Thus, we hypothesized that thiamine may modulate inflammation by alleviating metabolic shifts during immune cell activation. First, using allithiamine, which showed the most potent anti-inflammatory capacity among thiamine derivatives, we confirmed the inhibitory effects of allithiamine on the lipopolysaccharide (LPS)-induced pro-inflammatory cytokine production and maturation process in dendritic cells. We applied the LPS-induced sepsis model to examine whether allithiamine has a protective role in hyper-inflammatory status. We observed that allithiamine attenuated tissue damage and organ dysfunction during endotoxemia, even when the treatment was given after the early cytokine release. We assessed the changes in glucose metabolites during LPS-induced dendritic cell activation and found that allithiamine significantly inhibited glucose-driven citrate accumulation. We then examined the clinical implication of regulating metabolites during sepsis by performing a tail bleeding assay upon allithiamine treatment, which expands its capacity to hamper the coagulation process. Finally, we confirmed that the role of allithiamine in metabolic regulation is critical in exerting anti-inflammatory action by demonstrating its inhibitory effect upon mitochondrial citrate transporter activity. In conclusion, thiamine could be used as an alternative approach for controlling the immune response in patients with sepsis.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2116-2126
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• 2016

Bacterial biofilms are spatially structured communities that contain bacterial cells with a wide range of physiological states. The spatial distribution and speciation of copper in unsaturated Pseudomonas putida CZ1 biofilms that accumulated 147.0 mg copper per g dry weight were determined by transmission electron microscopy coupled with energy dispersive X-ray analysis, and micro-X-ray fluorescence microscopy coupled with micro-X-ray absorption near edge structure (micro-XANES) analysis. It was found that copper was mainly precipitated in a $75{\mu}m$ thick layer as copper phosphate in the middle of the biofilm, while there were two living cell layers in the air-biofilm and biofilm-medium interfaces, respectively, distinguished from the copper precipitation layer by two interfaces. The X-ray absorption fine structure analysis of biofilm revealed that species resembling $Cu_3(PO_4)_2$ predominated in biofilm, followed by Cu-Citrate- and Cu-Glutathione-like species. Further analysis by micro-XANES revealed that 94.4% of copper were $Cu_3(PO_4)_2$-like species in the layer next to the air interface, whereas the copper species of the layer next to the medium interface were composed by 75.4% $Cu_3(PO_4)_2$, 10.9% Cu-Citrate-like species, and 11.2% Cu-Glutathione-like species. Thereby, it was suggested that copper was initially acquired by cells in the biofilm-air interface as a citrate complex, and then transported out and bound by out membranes of cells, released from the copper-bound membranes, and finally precipitated with phosphate in the extracellular matrix of the biofilm. These results revealed a clear spatial pattern of copper precipitation in unsaturated biofilm, which was responsible for the high copper tolerance and accumulation of the biofilm.

• Current Research on Agriculture and Life Sciences
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• 제12권
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• pp.9-22
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• 1994

Soybean mosaic virus에 감수성 품종인 단경콩과 저항성 품종인 팔달콩의 cotyledon에 여러형태로 자극을 처리하였을때 유도되는 isoflavone aglycones(daidzein, genistein)와 이들 배당체들(daidzin, genistin)의 시간별 축적 정도를 조사하였다. UDP-glucose, $MgSO_4$, $HgCl_2$의 처리 및 Botrytis cinerea의 감염에 의하여 두 품종 모두 isoflavone aglycones와 이들 배당체들의 함량이 대조구(water 처리)와 비교하여 증가하였다. 그러나 citrate의 처리에 의해서는 isoflavone aglycones의 함량은 대조구와 큰 차이가 없었으나 isoflavone glucosides의 함량은 크게 증가하였다. UDP-glucose, $MgSO_4$ 및 $HgCl_2$의 처리에 의하여 isoflavone aglycones의 함량은 단경콩보다 팔달콩에서 크게 나타났다. 특히 daidzein의 경우, 단경콩보다 팔달콩에서 현저하게 크게 나타났다. 그러나 Botrytis cinerea의 감염에 의해서 daidzein의 최대 축적 양에는 두 품종 사이에 큰 차이가 없으나 최대 축적 시간은 팔달콩이 단경콩보다 빠르게 나타났다. 그리고 그 배당체인 daidzin과 geinstein의 축적은 단경콩보다 팔달콩에서 모든 자극처리에의해 높게 나타났다. UDP-glucose, $MgSO_4$, 및 $HgCl_2$의 처리에 의한 daidzein과 geinstein이 축적되는 양은 단경콩에서는 초기에는(24hr까지)에는 비슷하나, 48hr이후에는 daidzein의 축적이 geinstein의 함량보다 크게 나타났다. 그러나 팔달콩에서는 대체로 전 기간에서 daidzein의 함량이 geinstein의 함량보다 크게 나타났다. 병원균의 감염에 의해서는 두 품종에서 모두 daidzein의 양이 geinstein의 양보다 크게 나타났다.

• 한국동물학회지
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• 제11권3호
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• pp.75-82
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• 1968

培養 HeLa 細胞의 酸素消費量과 Lysine 吸收에 미치는 X-線 照射의 영향을 측정하였다. 1. 200r의 X-線 照射는 酸素消費量에 아무러한 영향이 없다. 酸素消費量은 succinate, citrate, 및 $\\alpha$-ketoglutarate에 의하여 增大되며 X-線 照射群에서도 이 傾向은 同一하다. 2. 酸素消費量에 미치는 sodium azide 와 2,4-dinitrophenol 의 영향은 X-線 照射에 의하여 상당히 변화된다. 3. Lysine의 初期吸收率은 X-線 照射에 의하여 甚히 低下되며, 또한 飽和吸收量도 減少된다. 4. Glucose는 lysine의 吸收를 促進시키고, succinate는 아무러한 영향이 없으며 citrate와 $\\alpha$-ketoglutarate는 억제한다. X-線 照射는 이러한 傾向에 아무런 변화를 초래하지 않는다. 5. Lysine의 吸收에 미치는 sodium azide와 2,4-dinitrophenol의 영향은 酸素消費量에 미치는 이들의 영향과 判異하다. 이러한 傾向은 X-線 照射群에서도 대체로 동일하다.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.819-824
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• 2010

We report the laser-induced formation of peanut-shaped gold nanoparticles (Au nanopeanuts) and gold nanowires (AuNWs), and their morphological properties. Pulsed laser irradiation of citrate-capped gold nanoparticles at 532 nm induces fragmentation, spherical growth, the formation of Au nanopeanuts, and the formation of AuNWs, sequentially. High-resolution transmission electron microscopy images reveal that the Au nanopeanuts are formed by instantaneous fusion of spherical nanoparticles in random orientation by laser heating. Furthermore, Au nanopeanuts are bridged in a linear direction to form AuNWs by an amorphous accumulation of gold atoms in the junction. The laser-produced Au nanopeanuts and AuNWs slowly disintegrate, restoring the spherical shape of the original Au nanoparticles when the laser irradiation is stopped. The addition of citrate effectively prevents them from transforming back to the nanospheres.