• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.117.2-117.2
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• 2003

The mechanism by which lead enters glial cells was examined. The uptake of lead reached saturation when assays were performed in buffers at pH 5.5 and 7.4. The Vmax and Km was 2.7 pmoles/mg protein/min and 13.4 M in the buffer at pH 7.4, respectively, whereas the Vmax and Km was 329 fmoles/mg and 8.2 M in the buffer at pH 5.5, respectively. Uptake in a buffer at pH 5.5 but not at pH 7.4 was inhibited by iron. Cells treated with the iron chelator desferoxamine displayed higher levels of the divalent metal transporter mRNA and protein. (omitted)

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.118-126
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• 2020

Silicon and phosphorus are elements that are beneficial for plant growth. Despite the abundant availability of silicate and phosphate in the Earth's crust, crop nutritional requirements for silicon and phosphorus are normally met through the application of fertilizer. However, fertilizers are one of the major causes of heavy metal pollution. In our study, we aimed to assess silicate and phosphate solubilization by the bacteria Enterobacter ludwigii GAK2, in the presence and absence of phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), to counteract cadmium stress in rice (Oryza sativa L). Our results showed that the GAK2-treated rice plants, grown in soil amended with phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), had significantly reduced cadmium content, and enhanced plant growth promoting characteristics including fresh shoot and root weight, plant height, and chlorophyll content. These plants showed significant downregulation of the cadmium transporter gene, OsHMA2, and upregulation of the silicon carrier gene, OsLsi1. Moreover, jasmonic acid levels were significantly reduced in the GAK2-inoculated plants, and this was further supported by the downregulation of the jasmonic acid related gene, OsJAZ1. These results indicate that Enterobacter ludwigii GAK2 can be used as a silicon and phosphorus bio-fertilizer, which solubilizes insoluble silicate and phosphate, and mitigates heavy metal toxicity in crops.

• Nutrition Research and Practice
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• 제2권4호
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• pp.317-321
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• 2008

Macrophages play a key role in iron metabolism by recycling iron through erythrophagocytosis. Ferroportin-l (FPN1) is a transporter protein that is known to mediate iron export from macrophages. Since divalent metals often interact with iron metabolism, we examined if divalent metals could regulate the expression of FPN1 in macrophages. J774 macrophage cells were treated with copper, manganese, zinc, or cobalt at 10, 50, or $100\;{\mu}M$ for 16 to 24 h. Then, FPN1 mRNA and protein levels were determined by quantitative real-time PCR and Western blot analyses, respectively. In addition, effects of divalent metals on FPN1 promoter activity were examined by luciferase reporter assays. Results showed that copper significantly increased FPN1 mRNA levels in a dose-dependent manner. The copper-induced expression of FPN1 mRNA was associated with a corresponding increase in FPN1 protein levels. Also, copper directly stimulated the activity of FPN1 promoter-driven reporter construct. In contrast, manganese and zinc had no effect on the FPN1 gene expression in J774 cells. Interestingly, cobalt treatment in J774 cells decreased FPN1 protein levels without affecting FPN1 mRNA levels. In conclusion, our study results demonstrate that divalent metals differentially regulate FPN1 expression in macrophages and indicate a potential interaction of divalent metals with the FPN1-mediated iron export in macrophages.

• Journal of Nutrition and Health
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• 제42권5호
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• pp.434-441
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• 2009

본 연구는 J774 대식세포에서 FPN 유전자 발현 조절에 구리가 미치는 영향을 알아보기 위하여 수행되었으며 그 결과는 다음과 같다. J774 대식 세포에 구리를 처리하였을 때, iron exporter FPN의 mRNA 수준이 농도 의존적으로 증가하는 것으로 나타났다. 반면, iron importer DMT1의 mRNA 수준은 구리 처리에 의해 영향을 받지 않았다. Actinomycin D를 이용하여 mRNA 합성을 억제한 상태에서 FPN mRNA 분해 정도를 시간별로 추적한 결과, acitnomycin D 처리 후 9시간 경과시 FPN mRNA 수준이 처음 수준의 약 60% 정도로 감소하였다. 배양액에 구리를 첨가한 경우에도 FPN mRNA의 분해 정도는 아무것도 처리하지 않은 대조군과 유의적인 차이가 없었으며, 이로 볼 때 구리는 FPN mRNA의 안정성에 영향을 미치지 않는 것으로 생각된다. 한편, reporter assay 실험 결과 구리의 첨가는 FPN 프로모터 활성을 유의적으로 증가시키는 것으로 나타나, 구리가 FPN mRNA의 전사 과정을 직접적으로 촉진함을 알 수 있었다. 또한, FPN 5'-UTR에 위치하는 IRE (iron response element)의 존재 여부는 구리에 의한 FPN 전사 개시 활성에 영향을 주지 않는 것으로 나타났으며, 이로 볼 때 구리는 철분과는 독립적인 작용 기작에 의해 FPN 유전자 발현을 조절하는 것으로 사료된다. 이상의 결과를 종합해 볼 때, 구리는 대식 세포에서 전사개시 과정을 활성화함으로써 농도 의존적으로 FPN 유전자 발현을 촉진하는 것으로 생각되며, 이는 구리가 철분의 대사에 미치는 새로운 작용 기작을 제시한다. 앞으로, 구리와 철 분의 상호 작용이 FPN의 철분 및 다른 무기질 이온의 세포내 외 수송 (transport)에 어떤 영향을 미치는지에 대한 기능적 연구가 계속적으로 이루어져야 할 것으로 사료된다.

• 생명과학회지
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• 제19권12호
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• pp.1685-1689
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• 2009

파이토킬레이트(PC)는 PCS에 의해 생성되는 작은 폴리펩타이드로서 여러 생물에서 발견되고 있다. PC의 역할은 카드뮴과 같은 중금속을 세포질에서 결합하며 이는 액포막에 존재하는 HMT에 의해서 액포 안으로 이동된다. HMT1은 분열효모에서 처음으로 알려졌으며 이후 선충, 초파리 등에서도 발견되었으며 세포 내 역할은 카드뮴 같은 중금속 해독에 관여를 하고 있다. 하지만 액포가 존재하지 않고 PC를 생성하지 않는 초파리에서의 HMT1의 발견은 그 동안 알려진 HMT1의 역할을 재 조명하게 된다. 따라서 PC를 생성하지 못하는 출아효모에 PC를 생성하는 분열효모 유래 SpHMT1을 발현시켜 카드뮴에 대한 저항성을 분석하였다. SpHMT1을 발현하는 출아효모는 카드뮴에 대한 저항성이 현저하게 증가되었고 이는 SpHMT1이 PC가 존재하지 않는 조건에서도 카드뮴에 대한 해독작용을 하는 것을 암시한다. 또한 SpHMT1을 발현하는 출아효모는 GSH에 대한 저항성을 보였고 카드뮴에 대한 저항성도 GHS에 의해서 더 증가되는 결과를 보였다. 이러한 결과는 HMT1이 PC와 결합된 카드뮴을 액포안으로 이동시키는 가능성보다 GSH와 결합된 카드뮴을 액포 안으로 이동시켜 카드뮴에 대한 해독작용을 한다는 것을 암시한다.

• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1132-1139
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• 2016

Brucellosis is a zoonotic disease caused by Brucella, a genus of gram-negative bacteria. Cytokines have key roles in the activation of innate and acquired immunities. Despite several research attempts to reveal the immune responses, the mechanism of Brucella infection remains unclear. Therefore, immune responses were analyzed in mice immunized with nine recombinant proteins. Cytokine production profiles were analyzed in the RAW 264.7 cells and naive splenocytes after stimulation with three recombinant proteins, metal-dependent hydrolase (r0628), bacterioferritin (rBfr), and thiamine transporter substrate-binding protein (rTbpA). Immune responses were analyzed by ELISA and ELISpot assay after immunization with proteins in mice. The production levels of NO, TNF-α, and IL-6 were time-dependently increased after having been stimulated with proteins in the RAW 264.7 cells. In naive splenocytes, the production of IFN-γ and IL-2 was increased after stimulation with the proteins. It was concluded that two recombinant proteins, r0628 and rTbpA, showed strong immunogenicity that was induced with Th1-related cytokines IFN-γ, IL-2, and TNF-α more than Th2-related cytokines IL-6, IL-4, and IL-5 in vitro. Conversely, a humoral immune response was activated by increasing the number of antigen-secreting cells specifically. Furthermore, these could be candidate diagnosis antigens for better understanding of brucellosis.

• Journal of Ginseng Research
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• 제46권2호
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• pp.248-254
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• 2022

Background: Zinc homeostasis is essential for human health and is regulated by several zinc transporters including ZIP and ZnT. ZIP4 is expressed in the small intestine and is important for zinc absorption from the diet. We investigated in the present study the effects of Panax ginseng (P. ginseng) extract on modulating Zip4 expression and cellular zinc levels in mouse Hepa cells. Methods: Hepa cells were transfected with a luciferase reporter plasmid that contains metal-responsive elements, incubated with P. ginseng extract, and luciferase activity was measured. Using ⁶⁵ZnCl₂, zinc uptake in P. ginseng-treated cells was measured. The expression of Zip4 mRNA and protein in Hepa cells was also investigated. Finally, using a luciferase reporter assay system, the effects of several ginsenosides were monitored. Results: The luciferase activity in cells incubated with P. ginseng extract was significantly higher than that of control cells cultured in normal medium. Hepa cells treated with P. ginseng extract exhibited higher zinc uptake. P. ginseng extract induced Zip4 mRNA expression, which resulted in an enhancement of Zip4 protein expression. Furthermore, some ginsenosides, such as ginsenoside Rc and Re, enhanced luciferase activity driven by intracellular zinc levels. Conclusion: P. ginseng extract induced Zip4 expression at the mRNA and protein level and resulted in higher zinc uptake in Hepa cells. Some ginsenosides facilitated zinc influx. On the basis of these results, we suggest a novel effect of P. ginseng on Zip4-mediated zinc influx, which may provide a new strategy for preventing zinc deficiency.