• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.35-43
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• 1997

Cis-dichlorodiammine platin${\mu}M$II (Cisplatin), an effective chemotherapeutic agent, induces acute renal failure by unknown mechanisms. To investigate direct toxic effects of cisplatin on the renal proximal tubular transport system, LLC-$PK_1$ cell line was selected as a cell model and the sugar transport activity was evaluated during a course of cisplatin treatment. Cells grown to confluence were treated with cisplatin for 60 min, washed, and then incubated for up to 5 days. At appropriate intervals, cells were tested for sugar transport activity using ${\alpha}-methyl-D-[^{14}C]glucopyranoside$ (AMG) as a model substrate. In cells treated with 100 ${\mu}M$ cisplatin, the AMG uptake was progressively impaired after 3 days. The viability of cells was not substantially changed with cisplatin of less than 100 ${\mu}M$, but it decreased markedly with 150 and 200 ${\mu}M$. In cisplatin-treated cells, the $Na^+$ -dependent AMG uptake was drastically inhibited with no change in the $Na^+$ -independent uptake. Kinetic analysis indicated that Vmax was suppressed, but Km was not altered. The $Na^+$ -dependent phlorizin binding was also decreased in cisplatin-treated cells. However, the AMG efflux from preloaded cells was not apparently retarded by cisplatin treatment. These data indicate that the cisplatin treatment impairs $Na^+$ -hexose cotransporters in LLC-$PK_1$ cells and suggest strongly that defects in transporter function at the luminal plasma membrane of the proximal tubular cells constitute an important pathogenic mechanism of cisplatin nephrotoxicity.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.59-59
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• 2018

Panax ginseng Meyer (Korean ginseng) is in the spotlight of Oriental medicine and is proclaimed as the king of medicinal plants owing to its adaptogenic characteristics. Ginseng root rot is a devastating disease caused by the fungus, Ilyonectria mors-panacis that generally attacks younger roots (~2 years), leading to defects in root quality, ginsenoside accumulation and also life cycle of the plant. Hence, there is an indispensable need to develop strategies resulting in tolerance against ginseng root rot. In the present study, we evaluated the effect of silica nanoparticles(N-SiO2) in Panax ginseng during I. mors-panacis infection. Long term analysis (30 dpi) revealed a striking 50% reduction in disease severity index upon 1mM and 2mM treatment of N-SiO2. However, N-SiO2 did not have any direct antifungal activity against I. mors-panacis. Membrane bound sugar efflux transporter, SWEET (Sugars Will Eventually be Exported Transporters) was identified in ginseng and as expected, its expression was suppressed upon N-SiO2 treatment in the root rot pathosystem. Furthermore, the total and reducing sugars in the apoplastic fluid clearly revealed that N-SiO2 regulates sugar efflux into apoplast. In a nut shell, N-SiO2 administration induces transcriptional reprogramming in ginseng roots, leading to regulated sugar efflux into apoplast resulting in enhanced tolerance against I. mors-panacis.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.4
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• pp.219-226
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• 2000

The application of recombinant DNA technology to restructure metabolic net-work can change metabolite and protein products by altering the biosynthetic pathways in an organism. Although some success has been achieved, a more detailed and thorough investigation of this approach is certainly warranted since it is clear that such methods hold great potential based on the encouraging results obtained so far. In last decade, there have been tremendous advances in the field of glycobiology and the stage has been set for the biotechnological production of glycoproteins for therapeutic use. Today glycoproteins are one of the most important groups of pharmaceutical products. In this study the attempt was made to focus on identifying technologies that may have general application for modifying glycosylation pathway of the yeast cells in order to produce glycoproteins of therapeutic use. The carbohydrates of therapeutic recombinant glycoproteins play very important roles in determining their pharmacokinetic properties. A number of biological interactions and biological functions mediated by glycans are also being targeted for therapeutic manipulation in vivo. For a commercially viable production of therapeutic glycoproteins a metabolic engineering of a host cell is yet to be established.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2127-2137
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• 2016

A mangrove microbial community was analyzed at the gene and protein levels using metagenomic and proteomic methods with the green macroalgae Enteromorpha prolifera as the substrate. Total DNA was sequenced on the Illumina HiSeq 2000 PE-100 platform. Two-dimensional gel electrophoresis in combination with liquid chromatography tandem mass spectrometry was used for proteomic analysis. The metagenomic data revealed that the orders Pseudomonadales, Rhizobiales, and Sphingomonadales were the most prevalent in the mangrove microbial community. By monitoring changes at the functional level, proteomic analyses detected ATP synthase and transporter proteins, which were expressed mainly by members of the phyla Proteobacteria and Bacteroidetes. Members of the phylum Proteobacteria expressed a high number of sugar transporters and demonstrated specialized and efficient digestion of various glycans. A few glycoside hydrolases were detected in members of the phylum Firmicutes, which appeared to be the main cellulose-degrading bacteria. This is the first report of multiple "omics" analysis of E. prolifera degradation. These results support the fact that key enzymes of glycoside hydrolase family were expressed in large quantities, indicating the high metabolic activity of the community.

• Molecules and Cells
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• v.40 no.10
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• pp.697-705
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• 2017

The maintenance of inorganic phosphate (Pi) homeostasis is essential for plant growth and yield. Plants have evolved strategies to cope with Pi starvation at the transcriptional, post-transcriptional, and post-translational levels, which maximizes its availability. Many transcription factors, miRNAs, and transporters participate in the Pi starvation signaling pathway where their activities are modulated by sugar and phytohormone signaling. Environmental stresses significantly affect the uptake and utilization of nutrients by plants, but their effects on the Pi starvation response remain unclear. Recently, we reported that Pi starvation signaling is affected by abiotic stresses such as salt, abscisic acid, and drought. In this review, we identified transcription factors, such as MYB, WRKY, and zinc finger transcription factors with functions in Pi starvation and other environmental stress signaling. In silico analysis of the promoter regions of Pi starvation-responsive genes, including phosphate transporters, microRNAs, and phosphate starvation-induced genes, suggest that their expression may be regulated by other environmental stresses, such as hormones, drought, cold, heat, and pathogens as well as by Pi starvation. Thus, we suggest the possibility of cross-talk between Pi starvation signaling and other environmental stress signaling pathways.

• Molecules and Cells
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• v.22 no.3
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• pp.343-352
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• 2006

Sialic acid is a sugar typically found at the N-glycan termini of glycoproteins in mammalian cells. Lec3 CHO cell mutants are deficient in epimerase activity, due to a defect in the gene that encodes a bifunctional UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE). Sialic acid modification on the cell surface is partially affected in these cells. We have mutagenized Lec3 CHO cells and isolated six mutants (termed C2m) deficient in the cell surface expression of polysialic acid (PSA). Mutant C2m9 was partially defective in expression of cell-surface PSA and wheat germ agglutinin (WGA) binding, while in the other five mutants, both cell-surface PSA and WGA binding were undetectable. PSA expression was restored by complementation with the gene encoding the CMP-sialic acid transporter (CST), indicating that CST mutations were responsible for the phenotypes of the C2m cells. We characterized the CST mutations in these cells by Northern blotting and RT-PCR. C2m9 and C2m45 carried missense mutations resulting in glycine to glutamate substitutions at amino acids 217 (G217E) and 256 (G256E), respectively. C2m13, C2m39 and C2m31 had nonsense mutations that resulted in decreased CST mRNA stability, and C2m34 carried a putative splice site mutation. PSA and CD15s expression in CST-deficient Lec2 cells were partially rescued by G217E CST, but not by G256E CST, although both proteins were expressed at similar levels, and localized to the Golgi. These results indicate that the novel missense mutations isolated in this study affect CST activity.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.844-855
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• 2017

Phosphate-solubilizing bacteria (PSB) have the ability to dissolve insoluble phosphate and enhance soil fertility. However, the growth and mineral phosphate solubilization of PSB could be affected by exogenous soluble phosphate and the mechanism has not been fully understood. In the present study, the growth and mineral phosphate-solubilizing characteristics of PSB strain Burkholderia multivorans WS-FJ9 were investigated at six levels of exogenous soluble phosphate (0, 0.5, 1, 5, 10, and 20 mM). The WS-FJ9 strain showed better growth at high levels of soluble phosphate. The phosphate-solubilizing activity of WS-FJ9 was reduced as the soluble phosphate concentration increased, as well as the production of pyruvic acid. Transcriptome profiling of WS-FJ9 at three levels of exogenous soluble phosphate (0, 5, and 20 mM) identified 446 differentially expressed genes, among which 44 genes were continuously up-regulated when soluble phosphate concentration was increased and 81 genes were continuously down-regulated. Some genes related to cell growth were continuously up-regulated, which would account for the better growth of WS-FJ9 at high levels of soluble phosphate. Genes involved in glucose metabolism, including glycerate kinase, 2-oxoglutarate dehydrogenase, and sugar ABC-type transporter, were continuously down-regulated, which indicates that metabolic channeling of glucose towards the phosphorylative pathway was negatively regulated by soluble phosphate. These findings represent an important first step in understanding the molecular mechanisms of soluble phosphate effects on the growth and mineral phosphate solubilization of PSB.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1189-1196
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• 2005

The cyclohexanol dehydrogenase (ChnA), produced by Rhodococcus sp. TK6, which is capable of growth on cyclohexanol as the sole carbon source, has been previously purified and characterized. However, the current study cloned the complete gene (chnA) for ChnA and its flanking regions using a combination of a polymerase chain reaction (PCR) based on the N-terminal amino acid sequence of the purified ChnA and plaque hybridization from a phage library of Rhodococcus sp. TK6. A sequence analysis of the 5,965-bp DNA fragment revealed five potential open reading frames (ORFs) designated as partial pte (phosphotriesterase), acs (acyl-CoA synthetase), scd (short chain dehydrogenase), stp (sugar transporter), and chnA (cyclohexanol dehydrogenase), respectively. The deduced amino acid sequence of the chnA gene exhibited a similarity of up to $53\%$ with members of the short-chain dehydrogenase/reductase (SDR) family. The chnA gene was expressed using the pET21 a(+) system in Escherichia coli. The activity of the expressed ChnA was then confirmed (13.6 U/mg of protein) and its properties investigated.

• Journal of Plant Biotechnology
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• v.36 no.1
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• pp.23-29
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• 2009

We have previously isolated a CCCH type zinc-finger protein gene, OsZF2 (Oryza sativa Zinc Finger 2), from the cold-treated rice cDNA library. To investigate the potential role of OsZF2, transgenic rice lines over-expressing OsZF2 under the control of CaMV 35S promoter have been developed through Agrobacterium-mediated transformation. Elevated level of OsZF2 transcripts was confirmed by RNA gel blot analysis in transgenic rice. Under the 100 mM NaCl condition, the transgenic rice showed significantly enhanced growth rate in terms of shoot length and fresh weight, implicating that OsZF2 is likely to be involved in salt response of rice. In the field condition, however, the transgenic rice showed a dwarf phenotype and flowering time was delayed. Genome expression profiling analysis of transgenic plants using the 20K NSF rice oligonucleotide array revealed many up-regulated genes related to stress responses and signaling pathways such as chaperone protein dnaJ 72, salt stress-induced protein, PR protein, disease resistance proteins RPM1 and Cf2/Cf5 disease resistance protein, carbohydrate/ sugar transporter, OsWAK kinase, brassinosteroid LRR receptor kinase, and jasmonate O-methyltransferase. These data suggest that the CCCH type zinc-finger protein OsZF2 is a upstream transcriptional factor regulating growth and stress responsiveness of rice.

• Journal of Life Science
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• v.31 no.8
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• pp.729-735
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• 2021

Type 2 diabetes occurs when there is an abnormality in the tissue's ability to absorb glucose. Glucose uptake and metabolism by insulin are the basic mechanisms that maintain blood sugar. Glucose uptake goes through various signaling steps initiated by the binding of insulin to receptors on the cell surface. In line with the foregoing, the purpose of this study was to investigate the effect of 2,7-phloroglucinol-6,6-bieckol (PHB), an active compound isolated from Ecklonia cava, on glucose uptake in 3T3-L1 adipocytes. Notably, PHB increased glucose uptake in a dose-dependent manner owing to the enhanced glucose transporter type 4 (GLUT4) expression in the plasma membrane of 3T3-L1 adipocytes. These effects of PHB were attributed to the phosphorylation of insulin receptor substrate-1 and protein kinase B (PKB or AKT), as well as to the phosphoinositide 3-kinase (PI3K) activation in the insulin signaling pathway. PHB also stimulated 5' AMP-activated protein kinase (AMPK) phosphorylation and activation. The phosphorylation and activation of the PI3K/AKT and AMPK pathways by PHB were identified using wortmannin (a PI3K inhibitor) and compound C (an AMPK inhibitor). In this study, we showed that PHB can increase glucose uptake in 3T3-L1 adipocytes by promoting GLUT4 translocation to the plasma membrane via the PI3K and AMPK pathways. The results indicate that PHB may help improve insulin sensitivity.