• Title/Summary/Keyword: Mechanisms of uptake

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An Overview of Phytoremediation Technology and Its Applications to Environmental Pollution Control (식물정화기술의 개요와 환경오염 제어에의 응용 현황)

  • Lee, Jae Heung
    • KSBB Journal
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    • v.27 no.5
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    • pp.281-288
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    • 2012
  • Phytoremediation-the use of plants for the in situ treatment of contaminated soil and water-has recently emerged as an inexpensive and user-friendly alternative to traditional methods of environmental clean-up. The present article outlines the characteristics of phytoremediation based on accumulated research evidence, along with discussions on its advantages and disadvantages. It further reviews various mechanisms involved in the phytoremediation processes: phytoextraction, rhizofiltration, phytostabilization, phytovolatilization and phytodegradation. Along the way, the author summarizes examples of its applications to environmental pollution control. These include wastewater treatment, removal of heavy metals, and hydrocarbons, remediation of recalcitrant contaminants, phytoremediation of radionuclides, and application of transgenic plants for enhanced biodegradation and phytoremediation. The remainder of the article briefly concludes with directions for future research.

Glucose Transporters and Insulin Action : Some Insights into Diabetes Management

  • Jung, Chan-Y.;Lee, Wan
    • Archives of Pharmacal Research
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    • v.22 no.4
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    • pp.329-334
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    • 1999
  • Insulin stimulates glucose uptake in muscle and adipose cells primarily by recruiting GLUT4 from an intracellular storage pool to the plasma membrane. Dysfunction of this process known as insulin resistance causes hyperglycemia, a hallmark of diabetes and obesity. Thus the understanding of the mechanisms underlying this process at the molecular level may give an insight into the prevention and treatment of these health problems. GLUT4 in rat adipocytes, for example, constantly recycles between the cells surface and an intracellular pool by endocytosis and exocytosis, each of which is regulated by an insulin-sensitive and GLUT4-selective sorting mechanism. Our working hypothesis has been that this sorting mechanism includes a specific interaction of a cytosolic protein with the GLUT4 cytoplasmic domain. Indeed, a synthetic peptide of the C-terminal cytoplasmic domain of GLUT4 induces an insulin-like GLUT4 recruitment when introduced in rat adipocytes. Relevance of these observations to a novel euglycemic drug design is discussed.

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Isolation and Identification of Phosphate Solubilizing Bacteria from Chinese Cabbage and Their Effect on Growth and Phosphorus Utilization of Plants

  • Poonguzhali, Selvaraj;Madhaiyan, Munusamy;Sa, Tong-Min
    • Journal of Microbiology and Biotechnology
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    • v.18 no.4
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    • pp.773-777
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    • 2008
  • Phosphate solubilizing bacteria (PSB) were isolated from the rhizosphere of Chinese cabbage and screened on the basis of their solubilization of inorganic tricalcium phosphate in liquid cultures. Ten strains that had higher solubilization potential were selected, and they also produced indole-3-acetic acid, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and siderophores. The strains were identified to be members of Pseudomonas, by 16S rDNA sequence analysis. Seed bacterization with PSB strains increased the root elongation and biomass of Chinese cabbage in seedling culture, although they had no effect on phosphorus uptake of plants. The plant growth promotion by PSB in this study could be due to the production of phytohormones or mechanisms other than phosphate solubilization, since they had no effect on P nutrition.

Fluorescently Labeled Nanoparticles Enable the Detection of Stem Cell-Derived Hepatocytes

  • Ha, Young-Eun;Shin, Jin-Sup;Lee, Dong-Yun;Rhim, Tai-Youn
    • Bulletin of the Korean Chemical Society
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    • v.33 no.6
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    • pp.1983-1988
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    • 2012
  • Stem cell transplantation is emerging as a possible new treatment for liver cirrhosis, and recent animal studies have documented the benefits of stem cell therapy in a hepatic fibrosis model. However, the underlying mechanism of stem cell therapy is still unclear. Among the proposed mechanisms, the cell replacement mechanism is the oldest and most important, in which permanently damaged tissue can be replaced by normal tissue to restore function. In the present study, Cy5.5-labeled superparamagnetic iron oxide (SPIO) was used to label human mesenchymal stem cells. The uptake of fluorescently labeled nanoparticles enabled the detection and monitoring of the transplanted stem cells; therefore, we confirmed the direct incorporation and differentiation of SPIO into the hepatocyte-like transplanted stem cells by detecting human tyrosine aminotransferase (TAT), well-known enzymatic marker for hepatocyte-specific differentiation.

Cellular Resistance to Antifolates (항엽산제에 대한 세포의 저항성 기작)

  • 김정상
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.22 no.6
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    • pp.839-845
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    • 1993
  • One of the major problems of cancer chemotheraphy is the development of drug resistance in tumors, resulting in reduced responsiveness to subsequent treatments. The folate antagonists are being used to treat such diverse illnesses as cancer, leukemia, psoriasis, rheumatoid arthritis, etc. Previous studies have established that resistance to antifolates may occur in mammalian tumor cells by one or more of five mechanisms ; (a) an increase in the levels of the target enzyme, generally as a consequence of gene amplification ; (b) an alteration in the target enzyme, leading to an enzyme with a decreased binding affinity for the drug ; (c) a decrease in the uptake of the drug into the cells ; (d) increased extrusion of drugs out of cells ; (e) impaired ability to polyglutamylate the parent drug which is capable of being intracellularly metabolized to longer chain length.

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Blue light signaling in stomatal guard cells

  • Shimazaki, Ken-ichiro;Michio Doi;Toshinori Kinoshita
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.86-89
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    • 2002
  • Blue light activates proton pump, and creates electrical gradient across the plasma membrane and drives $K^{+}$ uptake in stomatal guard cells. In this presentation, we provide evidence for regulatory mechanisms of the pump and the identification of blue light receptor. The pump is shown to be the plasma membrane H$^{+}$- ATPase and is activated through phosphorylation of the C-terminus. Phosphorylation occurred and 14-3-3 protein bound to the phosphorylation site. The binding of 14-3-3 protein was required for the H$^{+}$-ATPase activation. We also found that phot1 phot2 double mutant does not respond to blue light but other mutants respond to blue light by stomatal opening. However, all these mutants are capable of stomatal opening in the presence of fusicoccin, an activator of the H$^{+}$-ATPase. These results suggest that both photl and phot2 act as blue light receptors in guard cells.d cells.

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Diabetes, Glucose Transport and Hypoglycaemic Agents

  • Khil, Lee-Yong
    • Biomolecules & Therapeutics
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    • v.12 no.4
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    • pp.202-208
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    • 2004
  • Diabetes mellitus is a complex metabolic derangement with hyperglycaemia being the most characteristic symptom of diabetes. Hyperglycaemia can be caused by an increase in the rate of glucose production by the liver or by a decrease in the rate of glucose use by peripheral tissues. Impaired glucose transport is one of the major factors contributing to insulin resistance in type 2 diabetic patients. The ability of insulin to mediate tissue glucose uptake is a critical step in maintaining glucose homeostasis and in clearing the post-prandial glucose load. Glucose transport is mediated by specific carriers called glucose transporters (GLUTs). In this article, the functional importance and molecular mechanisms of insulin-induced glucose transport and development of hypoglycaemic agents which increase glucose transport are reviewed.

Sodium/chloride-Dependent Transporters: Elucidation of Their Properties Using the Dopamine Transporter

  • Caron, Marc G.
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1994.04a
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    • pp.88-93
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    • 1994
  • The mechanisms controlling the intensity and duration of synaptic transmission are numerous. Once an action potential reaches a nerve terminal, the stored neurotransmitters are released in a quantum fashion into the synaptic cleft. At that point neurotransmitters can act on post-synaptic receptors to elicit an action on the post-synaptic cell or net at so-called auto-receptors that are located on the presynaptic side and which often regulate the further release of the neutotransmitter. Whereas the action of the neurotransmitter receptors is regulated by desensitization phenomenon, the major mechanism by which the intensity and duration of neurotransmitter action is presumably regulated by either its degradation or its removal from the synaptic cleft. In the central nervous system, specialized proteins located in fe plasma membrane of presynaptic terminals function to rapidly remove neurotransmitters from the synaptic cleft in a sodium chloride-dependent fashion. These proteins have been referred to as uptake sites or neurotransmitter transporters. Once taken up by the plasma membrane transporters, neurotransmitters are repackaged into secretory vesicles by distinct transporters which depend on a proton gradient.

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Properties and Disalinization of Salt-affected Soil (간척지 염해토양의 특성과 제염기법)

  • Son, Jae-Kwon;Song, Jae-Do;Shin, Won-Tae;Lee, Su-Hwan;Ryu, Jin-Hee;Cho, Jae-Young
    • Korean Journal of Organic Agriculture
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    • v.24 no.2
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    • pp.273-287
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    • 2016
  • Accumulation of excessive salt in Reclaimed coastal tidelands can reduce crop yields, reduce the effectiveness of irrigation, degradation of soil structure, and affect other soil properties. These salts has shown to cause specific ions in the plant over a period of time leads to ion toxicity or ion imbalance and a continuous osmotic phase that prevents water uptake by plants due to osmotic pressure of saline soil solution. This review focuses on the characteristics of salt-affected soils, mechanisms of salt-tolerance plants, desalinization technology, and soil management to maintain sustainable agro-ecosystem in salt-affected soils.

A Time to Fast, a Time to Feast: The Crosstalk between Metabolism and the Circadian Clock

  • Kovac, Judit;Husse, Jana;Oster, Henrik
    • Molecules and Cells
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    • v.28 no.2
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    • pp.75-80
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    • 2009
  • The cyclic environmental conditions brought about by the 24 h rotation of the earth have allowed the evolution of endogenous circadian clocks that control the temporal alignment of behaviour and physiology, including the uptake and processing of nutrients. Both metabolic and circadian regulatory systems are built upon a complex feedback network connecting centres of the central nervous system and different peripheral tissues. Emerging evidence suggests that circadian clock function is closely linked to metabolic homeostasis and that rhythm disruption can contribute to the development of metabolic disease. At the same time, metabolic processes feed back into the circadian clock, affecting clock gene expression and timing of behaviour. In this review, we summarize the experimental evidence for this bimodal interaction, with a focus on the molecular mechanisms mediating this exchange, and outline the implications for clock-based and metabolic diseases.