• Journal of the Korean Magnetic Resonance Society
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• v.19 no.1
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• pp.42-48
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• 2015

The mannitol transporter Enzyme $II^{Mtl}$ of the bacterial phosphotransferase system has two cytoplasmic phosphoryl transfer domains $IIA^{Mtl}$ and $IIB^{Mtl}$. The two domains are linked by a flexible peptide linker in mesophilic bacterial strains, whereas they are expressed as separated domains in thermophilic strains. Here, we carried out backbone assignment of $IIA^{Mtl}$ from thermophilic Thermoanaerobacter Tencongensis using a suite of heteronuclear triple resonance NMR spectroscopy. We have completed 94% of the backbone assignment, and obtained secondary structural information based on torsion angles derived from the chemical shifts. $IIA^{Mtl}$ of Thermoanaerobacter Tencongensis is predicted to have six ${\beta}$ strands and six ${\alpha}$ helices, which is analogous to $IIA^{Mtl}$ of Escherichia coli.

• YAKHAK HOEJI
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• v.47 no.4
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• pp.224-229
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• 2003

We have investigated the transport characteristics of synthetic antioxidant and free radical scavenger, $\alpha$-phenyl-n-tert-butyl nitrone (PBN) at the blood-brain barrier (BBB) by in vitro uptake study in conditionally immortalized rat brain capillary endothelial cell line (TR-BBB). Also, the efflux of PBN from brain to blood is estimated using the brain efflux index (BEI) method. Choline is a charged organic cation, including nitrogen-methyl group and shows the carrier-mediated distribution to the brain. [$^3$H]Choline uptake by TR-BBB cells was significantly inhibited by PBN with $IC_{50}$/ of 1.2 mM, which appears to be due to similar structures between choline and PBN. And, PBN was microinjected into Par2 of the rat brain by BEI method, and was eliminated from the brain with an apparent elimination half-life of about 2 min. Also, [$^3$H]choline efflux was significantly inhibited by PBN using BEI method. In conclusion, the efflux transport of PBN takes place across the BBB and PBN may be transported into the brain and eliminated from the brain by BBB choline transporter.

• BMB Reports
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• v.56 no.2
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• pp.56-64
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• 2023

Nitrogen (N) is an essential macronutrient required for plant growth and crop production. However, N in soil is usually insufficient for plant growth. Thus, chemical N fertilizer has been extensively used to increase crop production. Due to negative effects of N rich fertilizer on the environment, improving N usage has been a major issue in the field of plant science to achieve sustainable production of crops. For that reason, many efforts have been made to elucidate how plants regulate N uptake and utilization according to their surrounding habitat over the last 30 years. Here, we provide recent advances focusing on regulation of N uptake, allocation of N by N transporting system, and signaling pathway controlling N responses in plants.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.15-22
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• 2006

A 4,971 bp chromosomal DNA fragment containing the pqrA, paraquat resistance gene, was cloned from Ochrobactrum anthropi JW-2, and the complete nucleotide sequence was determined. Nucleotide and deduced amino acid sequences of the fragment revealed the presence of 4 complete ORFs (orf2, pqrA, orf3, orf4) and two incomplete ORFs(orf1, orf5). Orf1, pqrA, orf4 and orf5 exists at the direct strand but orf2 and orf3 exists at the reverse complementary strand. Orf1 which of incomplete sequences without start codon shares homology with ATP binding region of the response regulator receiver. Orf2 shares high homology with members of the tetR family of transcriptional repressor which have a helix-turn-helix (H-T-H) motif. Therefore, the orf2 is predicted as a transcriptional repressor of pqrA and is designated as pqrR2. Orf3 shares high homology with the members of the lysR family acting as a transcriptional activator which have both of a H-T-H motif at the N-terminal region and substrate binding domain at the C-terminal region. Therefore, the orf3 is predicted as a transcriptional activator of pqrA and is designated as pqrR1. Orf4 shows homology with the periplasmic substrate-binding protein of amino acid ABC transporter. Orf5 which of incomplete sequences without stop codon revealed the homology with the permeases protein of amino acid ABC transporter.

• Animal Bioscience
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• v.35 no.12
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• pp.1921-1928
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• 2022

Objective: This research aimed to evaluate the effects of age on growth, tibia development, and intestinal calcium (Ca) and phosphorus (P) transporter gene expressions in broiler chickens. Methods: A total of 224 male Arbor Acres broilers were fed with nutrient-adequate diets and reared in eight cages (28 broilers per cage). Eight broilers (one broiler per cage) were selected and killed at 5, 10, 15, 20, 25, 30, 35, and 40 days of age, respectively. Results: Body weight continuously increased with age of broiler chickens from 5 to 40 days. The bone weight, ash weight, diameter, and length of the tibia also increased with broiler age. By contrast, the tibia ash, Ca, and P percentages quadratically changed with age (p<0.001), and the highest values of mineral contents were observed at 20, 25, and 25 days of age, respectively. The mRNA abundances of calcium-binding protein 28-kDa (CaBP-D28k), sodium-calcium exchanger 1 (NCX1), and plasma membrane ATPase 1b (PMCA1b) increased from 5 to 25 days and then decreased up to 40 days. Similar results were noted in the mRNA abundances of IIb sodium-phosphate cotransporter (NaPi-IIb), inorganic phosphate transporter 1 (PiT-1), inorganic phosphate transporter 2 (PiT-2), nuclear vitamin D receptor (nVDR), and membrane vitamin D receptor (mVDR). The mRNA abundances of Ca and P transporters and VDRs were the highest at 25 days of age. Conclusion: These data indicate that age quadratically affects intestinal Ca and P transporter gene expression and mineral absorption capacity in broiler chickens.

• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.293-302
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• 2002

The classical concept for iron uptake into mammalian cells has been the endocytosis of transferrin( $T_{f}$ )-bound F $e^{3+}$ via the $T_{f}$ - $T_{f}$ receptor cycle. In this case, we could not explain the uptake of F $e^{2＋}$ ion and the export of iron from endosome. Studies on iron transport revealed that other transport system exists in epithelial cells of the intestine. One of non- $T_{f}$ -receptor-mediated transport systems is Nramp2/DMT1/DCT1 which transports M $n^{＋＋}$, $Mg^{＋＋}$, Z $n^{＋＋}$, $Co^{＋＋}$, N $i^{＋＋}$ or C $u^{＋＋}$ ion as well as F $e^{+2}$ ion. DMT1 was cloned from intestines of iron-deficient rats and shown to be a hydrogen ion-coupled iron transporter and a protein regulated by absorbed dietary iron. DMT1 is founded in other cells such as cortical and hippocampal glial cells as well as endothelial cells in duodenum. Two F $e^{3+}$ ion bound to transferrin( $T_{f}$ ) are taken up via the $T_{f}$ - $T_{f}$ receptor cycle in the intestinal epithelial cell. F $e^{3+}$ in endosome was converted to F $e^{2＋}$ ion, and then exported to cytosol via DMT1. F $e^{2＋}$ ion is taken up into cytosol via DMT1. Several other transporters such as FET, FRE, CCC2, AFT1, SMF, FTR, ZER, ZIP, ZnT and CTR have been reported recently and dysfunction of the transporters are related with diseases containing Wilson's disease, Menkes disease and hemochromatosis. Evidences from several studies strongly suggest that DMT1 is the major transporter of iron in the intestine and functions critically in transport of other metal ions.

• Molecules and Cells
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• v.25 no.1
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• pp.50-54
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• 2008

The vesicular glutamate transporter (VGLUT) transports glutamate into pre-synaptic vesicles. Three isoforms of VGLUT have been identified in humans, but their functional differences remain largely unknown. EAT-4 is the only homologue of human VGLUT in C. elegans. Here we report that mutants of eat-4 exhibit hyperforaging behavior and that each of the isoforms of human VGLUT functionally rescues the defects in eat-4 worms.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.113-117
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• 2016

As a neurotransmitter, serotonin plays important roles in brain. It relates various neuropsychiatric disorders such as anxiety, depression, schizophrenia. [$^{11}C$]DASB is a well-known PET tracer for serotonin transporter imaging. In this study, we synthesized [$^{11}C$]DASB in HPLC loop for simple and rapid production. Total synthesis time was about 40 minutes and the radiochemical purities were over 99%. The specific activity was $51.4GBq/{\mu}mole$ (n=16). [$^{11}C$]DASB showed highest uptake in mid-brain that serotonergic nerves are abundant and lowest uptake in cerebellum. In conclusion, we used HPLC loop method for [$^{11}C$]DASB labeling and this method is useful for production of $^{11}C$ labeled PET tracers.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1047-1053
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• 2022

When ptsG, a glucose-specific phosphotransferase system (PTS) component, is deleted in Escherichia coli, growth can be severely poor because of the lack of efficient glucose transport. We discovered a new PTS transport system that could transport glucose through the growth-coupled experimental evolution of ptsG-deficient E. coli C strain under anaerobic conditions. Genome sequencing revealed mutations in agaR, which encodes a repressor of N-acetylgalactosamine (Aga) PTS expression in evolved progeny strains. RT-qPCR analysis showed that the expression of Aga PTS gene increased because of the loss-of-function of agaR. We confirmed the efficient Aga PTS-mediated glucose uptake by genetic complementation and anaerobic fermentation. We discussed the discovery of new glucose transporter in terms of different genetic backgrounds of E. coli strains, and the relationship between the pattern of mixed-acids fermentation and glucose transport rate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.758-763
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• 2003

Amino acid transporters play an important role in supplying nutrients to normal and cancer cells for cell proliferation. System L is a major transport system responsible for the N $a^{＋}$-independent, large neutral amino acids including several essential amino acids. L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed presumably to support their continuous growth and proliferation in malignant tumors. 2-Aminobicyclo- (2,2,1) -heptane-2-carboxylic acid (BCH) is a model compound for study of amino acid transporter as a system L selective inhibitor. In the present study, we examined whether BCH induced growth inhibition in KB human oral squamous carcinoma cell line or not. The uptake of L-［$^{14}$ C］leucine by KB cells is inhibited by BCH in a concentration dependent manner with a Ι $C_{50}$ value of 75.3$\pm$6.2 ${\mu}{\textrm}{m}$ and a $K_{i}$ value of 98.7$\pm$ 4.1 ${\mu}{\textrm}{m}$. The growth of KB cells is inhibited by BCH in time dependent manner and concentration dependent manner with a Ι $C_{50}$ value of 11.1 $\pm$0.8 mM. In the DNA of KB cells treated with the various concentrations and various periods of BCH, the characteristic ladders associated with DNA fragmentation were not observed. These results suggest that BCH inhibits the growth of KB oral epidermoid carcinoma cells through the inhibition of transport of neutral amino acids into cells without DNA break down. This phenomenon will be a new rationale for anti-cancer therapy.y.