• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.2 no.1
• /
• pp.51-55
• /
• 2016

Organofluorine compounds have become increasingly important as pharmaceuticals, radiopharmaceuticals, agrochemicals, and material science. Recent advances on the efficient introduction of fluorine to organic molecules are mainly results of development of transition metal catalysts and fluorination reagents. Among the various fluorination reagents, we have been interested in developing more efficient sulfur-based deoxyfluorinating reagents. Here we report various electronic properties of five popular sulfur-based deoxyfluorinating reagents using density functional theory calculation. We believe that the theoretical study on the reagents will assist the rational design of new deoxyfluorinating reagents.

• Journal of the Korean Chemical Society
• /
• v.63 no.5
• /
• pp.352-359
• /
• 2019

The most important parameter of organic molecules for energy harvesting application focuses mainly on their band gap (HOMO-LUMO). In this report, we synthesized differently substituted 1,3,5-triazine based organic molecule which on future processing can be used in organic electronics like solar cells and OLED's. The energy gap of the synthesized novel analogue was calculated using cyclic voltammetry, UV-Visible spectroscopy and compared with density functional theory (DFT) studies.

• Corrosion Science and Technology
• /
• v.21 no.1
• /
• pp.21-31
• /
• 2022

Potentiodynamic polarization, EIS measurements, quantum chemical calculations, and molecular dynamic simulations were used to investigate the corrosion behavior of mild steel in 0.5 M aqueous hydrochloric acid medium in the presence or absence of nystatin drug. Potentiodynamic tests suggested that this molecule could act as a mixed inhibitor due to its adsorption on the mild steel surface. The objective of this study was to exploit theoretical calculations to gain a better understanding mechanism of inhibition. Calculating the adsorption behavior of the investigated molecule on Fe (1 1 0) surface was accomplished using Monte Carlo simulation. Molecules were also investigated using Density Functional Theory (DFT), specifically PBE functional, in order to identify the link between molecular structure and corrosion inhibition behavior of the compound under investigation. Adsorption energies between nystatin and iron were estimated more accurately by utilizing Molecular Mechanics calculation with Periodic Boundary Conditions (PBC). Estimated theoretical parameters significantly assisted our understanding of the corrosion inhibition mechanism exhibited by this molecule. They were found to be in accord with experimental results.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.45 no.1
• /
• pp.17-21
• /
• 2022

The present study aimed to determine whether a hemolymph prepared from Antheraea yamamai larvae had the same biological activities using a Bombyx mori hemolymph prior to exposure to lipopolysaccharide (LPS) in order to induce an inflammatory response. The effects of the hemolymph were determined using a reverse transcription-quantitative polymerase chain reaction to assess the expression of pro-inflammatory molecules. The A. yamamai hemolymph exerted anti-inflammatory effects on LPS-activated human monocytic leukemia cells via Toll-like receptor (TLR) 4-mediated suppression, similar to the B. mori hemocyte extract. Treatment with the A. yamamai hemolymph significantly suppressed LPS-induced upregulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression at all tested concentrations compared with the control, similar to the B. mori immune-challenged hemolymph. Finally, the A. yamamai hemolymph, like the B. mori immune-challenged hemolymph, suppressed all of these concentrations in a dose-independent manner. These results demonstrate that the hemolymph of A. yamamai exhibited important biologically active substances. Further in-depth functional studies are required to fully understand the mechanisms underlying the biological activities of wild-type silkworm hemolymphs.

• Molecules and Cells
• /
• v.45 no.3
• /
• pp.101-108
• /
• 2022

Drosophila melanogaster lymph gland, the primary site of hematopoiesis, contains myeloid-like progenitor cells that differentiate into functional hemocytes in the circulation of pupae and adults. Fly hemocytes are dynamic and plastic, and they play diverse roles in the innate immune response and wound healing. Various hematopoietic regulators in the lymph gland ensure the developmental and functional balance between progenitors and mature blood cells. In addition, systemic factors, such as nutrient availability and sensory inputs, integrate environmental variabilities to synchronize the blood development in the lymph gland with larval growth, physiology, and immunity. This review examines the intrinsic and extrinsic factors determining the progenitor states during hemocyte development in the lymph gland and provides new insights for further studies that may extend the frontier of our collective knowledge on hematopoiesis and innate immunity.

• Journal of Applied Biological Chemistry
• /
• v.52 no.3
• /
• pp.93-102
• /
• 2009

Polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have significantly beneficial effects on health in relation to cardiovascular, immune, and inflammatory conditions and they are involved in determining the biophysical properties of membranes as well as being precursors for signaling molecules. PUFA biosynthesis is catalyzed by sequential desaturation and fatty acyl elongation reactions. This aerobic biosynthetic pathway was thought to be taxonomically conserved, but an alternative anaerobic pathway for the biosynthesis of PUFA is now known to contain analogous polyketide synthases (PKS). Certain fish oil can be a rich source of PUFA although processed marine oil is generally undesirable as food ingredients because of the associated objectionable flavors that are difficult and cost-prohibitive to remove. Oil-seed plants contain only the 18-carbon polyunsaturated fatty acid alpha-linolenic acid, which is not converted in the human body to EPA and DHA. It is now possible to engineer common oilseeds which can produce EPA and DHA and this has been the focus of a number of academic and industrial research groups. Recent advances and future prospects in the production of EPA and DHA in oilseed crops are discussed here.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.6
• /
• pp.969-975
• /
• 2003

Two conserved amino acid residues in the extra sugar-binding space near the catalytic site of Thermus maltogenic amylase (ThMA) were analyzed for their role in the hydrolysis and transglycosylation activity of the enzyme. Site-directed mutagenesis was carried out by replacing N33l with a lysine (N331K), E332 with a histidine (E332H), or by replacing both residues at the same time (N331K/E332H). The measured $K_m$ values indicated that affinities toward all substrates tested, including starch, pullulan, ${\beta}-cyclomaltodextrin$, and acarbose, were lower in all the mutants compared to that of wild-type ThMA, leading to reduced hydrolysis activity. In addition, the lower ratio of transglycosylation to hydrolysis in the mutants compared to that in the wild-type ThMA indicated that these mutants preferred hydrolysis to the transglycosylation reaction. These results demonstrated that the conserved dipeptide at 331 and 332 of ThMA is directly involved in the formation and accumulation of transfer products by accommodating acceptor sugar molecules.

• Molecules and Cells
• /
• v.27 no.3
• /
• pp.271-277
• /
• 2009

Proteins interact with each other within a cell, and those interactions give rise to the biological function and dynamical behavior of cellular systems. Generally, the protein interactions are temporal, spatial, or condition dependent in a specific cell, where only a small part of interactions usually take place under certain conditions. Recently, although a large amount of protein interaction data have been collected by high-throughput technologies, the interactions are recorded or summarized under various or different conditions and therefore cannot be directly used to identify signaling pathways or active networks, which are believed to work in specific cells under specific conditions. However, protein interactions activated under specific conditions may give hints to the biological process underlying corresponding phenotypes. In particular, responsive functional modules consist of protein interactions activated under specific conditions can provide insight into the mechanism underlying biological systems, e.g. protein interaction subnetworks found for certain diseases rather than normal conditions may help to discover potential biomarkers. From computational viewpoint, identifying responsive functional modules can be formulated as an optimization problem. Therefore, efficient computational methods for extracting responsive functional modules are strongly demanded due to the NP-hard nature of such a combinatorial problem. In this review, we first report recent advances in development of computational methods for extracting responsive functional modules or active pathways from protein interaction network and microarray data. Then from computational aspect, we discuss remaining obstacles and perspectives for this attractive and challenging topic in the area of systems biology.

• Molecules and Cells
• /
• v.28 no.6
• /
• pp.553-558
• /
• 2009

In the periphery, a galectin-1 receptor, CD7, plays crucial roles in galectin-1-mediated apoptosis of activated T-cells as well as progression of T-lymphoma. Previously, we demonstrated that $NF-{\kappa}B$ downregulated CD7 gene expression through the p38 MAPK pathway in developing immature thymocytes. However, its regulatory pathway is not well understood in functional mature T-cells. Here, we show that CD7 expression was downregulated by Twist2 in Jurkat cells, a human acute T-cell lymphoma cell line, and in EL4 cells, a mature murine T-cell lymphoma cell line. Furthermore, ectopic expression of Twist2 in Jurkat cells reduced galectin-1-induced apoptosis. While full-length Twist2 decreased CD7 promoter activity, a C-terminal deletion form of Twist2 reversed its inhibition, suggesting an important role of the C-terminus in CD7 regulation. In addition, CD7 expression was enhanced by histone deacetylase inhibitors such as trichostatin A and sodium butyrate, which indicates that Twist2 might be one of candidate factors involved in histone deacetylation. Based on these results, we conclude that upregulation of Twist2 increases the resistance to galectin-1-mediated-apoptosis, which may have significant implications for the progression of some T-cells into tumors such as Sezary cells.

• Membrane and Water Treatment
• /
• v.7 no.1
• /
• pp.23-38
• /
• 2016

Batch adsorption of methyl orange (MO) from aqueous solution using three kinds of anion exchange membranes BI, BIII and DF-120B having different ion exchange capacities (IECs) and water uptakes ($W_R$) was investigated at room temperature. The FTIR spectra of anion exchange membranes was analysed before and after the adsorption of MO dye to investigate the intractions between dye molecules and anion exchange membranes. The effect of various parameters such as contact time, initial dye concentration and molarity of NaCl on the adsorption capacity was studied. The adsorption capacity found to be increased with contact time and initial dye concentration but decreased with ionic strength. The adsorption of MO on BI, BIII and DF-120B followed pseudo-first-order kinetics and the nonlinear forms of Freundlich and Langmuir were used to predict the isotherm parameters. This study demonstrates that anion exchange membranes could be used as useful adsorbents for removal of MO dye from wastewater.