Biomedical subjects
Publications and source records attributed to Jong-Man Kim.
Reversible ribbon-sphere microstructural transformation of dipeptide-containing diacetylene supramolecules was observed by specific ligand-receptor interactions.
Self-assembled diacetylene vesicles were spotted and immobilized on aldehyde-modified glass substrates using conventional microarray technology. Irradiation of the immobilized diacetylenes allowed generation of nonfluorescent "blue-phase" polydiacetylene (PDA) arrays. Specific interaction of the PDA vesicle arrays with carbohydrates or poly(acrylic acid) solutions afforded fluorescent profiles.
The natural binding of streptavidin (STA) for a small molecule, biotin, has made it a useful tool in specific targeting application, due to their most specific noncovalent biological interactions in nature. Here, we describe a polydiacetylene (PDA)-based colorimetric biosensor to detect the STA-biotin interactions. We synthesized two kinds of biotin-labeled 10,12-pentacosadiynoic acid (PCDA) monomers having 2(ethylene oxide) or 3(ethylene oxide) spacer and prepared biotin-modified PDA liposomes using them. Upon the addition of STA, the modified PDA liposomes showed a color change from blue to red in about 1h followed by their aggregation and precipitation. The aggregation was found to be due to the cross-linking between the PDA liposomes caused by the STA having four biotin binding sites, which was confirmed by their TEM analysis. Since the STA-biotin interactions are widely adopted for various biological detection systems; the biotin-modified PDA sensor developed in this study has enormous potentials for the development of various colorimetric biosensors.
Selective removal of t-Boc protecting groups in a polymer film imbedded, pyrene-containing calixarene derivative results in the generation of a patterned fluorescence image without employing wet developing processes.
The population structure of the Bacillus cereus group (52 strains of B. anthracis, B. cereus, and B. thuringiensis) was investigated by sequencing seven gene fragments (rpoB, gyrB, pycA, mdh, mbl, mutS, and plcR). Most of the strains were classifiable into two large subgroups in six housekeeping gene trees but not in the plcR tree. In addition, several consistent clusters were identified, which were unrelated to species distinction. Moreover, interrelationships among these clusters were incongruent in each gene tree. The incongruence length difference test and split decomposition analyses also showed incongruences between genes, suggesting horizontal gene transfer. The plcR gene was observed to have characteristics that differed from those of the other genes in terms of phylogenetic topology and pattern of sequence diversity. Thus, we suggest that the evolutionary history of the PlcR regulon differs from those of the other chromosomal genes and that recombination of the plcR gene may be frequent. The homogeneity of B. anthracis, which is depicted as an independent lineage in phylogenetic trees, is suggested to be of recent origin or to be due to the narrow taxonomic definition of species.
To investigate the role of hydrogen-bonding on colorimetric transition of polydiacetylene supramolecules, novel diacetylene derivatives allowing various hydrogen-bonding states were synthesized by coupling carboxy-substituted (ortho-, meta-, and para-) anilide groups with a typical single-chain diacetylene lipid. One with a terminal carboxyl group at the meta position provided the resulting supramolecular Langmuir-Schaefer films with enhanced hydrogen-bonding, and hence resulted in unprecedented colorimetric reversibility under both thermal and pH stimuli.
Comparative sequence analysis was performed upon Bacillus anthracis and its closest relatives, B. cereus and B. thuringiensis. Portions of rpoB DNA from 10 strains of B. anthracis, 16 of B. cereus, 10 of B. thuringiensis, 1 of B. mycoides, and 1 of B. megaterium were amplified and sequenced. The determined rpoB sequences (318 bp) of the 10 B. anthracis strains, including five Korean isolates, were identical to those of Ames, Florida, Kruger B, and Western NA strains. Strains of the "B. cereus group" were separated into two subgroups, in which the B. anthracis strains formed a separate clade in the phylogenetic tree. However, B. cereus and B. thuringiensis could not be differentiated. Sequence analysis confirmed the five Korean isolates as B. anthracis. Based on the rpoB sequences determined in the present study, multiplex PCR generating either B. anthracis-specific amplicons (359 and 208 bp) or cap DNA (291 bp) in a virulence plasmid could be used for the rapid differential detection and identification of virulent B. anthracis.
OBJECTIVE: Prostaglandin E2 (PGE2) has a wide range of regulatory action in diverse cell types. To investigate the role of PGE2 in rheumatoid arthritis (RA), we tested the effect of exogenous PGE2 on the production of cytokines in synoviocytes. METHODS: Fibroblast-like synoviocytes (FLS) were prepared from the synovial tissue of patients with RA and cultured in the presence of PGE2. The production of interleukin 15 (IL-15) and IL-10 were measured in culture supernatant by ELISA. IL-15 mRNA expression and nuclear factor-kappaB binding activity for IL- 15 transcription were determined by reverse transcription-polymerase chain reaction and electrophoresis mobility shift assay (EMSA), respectively. The level of IL-15 production was also measured by Western blot. RESULTS: PGE2 at concentrations from 10(-11) to 10(-5) M inhibited secretion of IL-15 by FLS, while increasing IL-10 production, in a dose dependent manner. IL-15 production stimulated by interferon-gamma (IFN-gamma), IL-1beta, or lipopolysaccharide were also strongly inhibited by PGE2. This PGE2-mediated inhibition of IL-15 production appears to be dependent in part on the increase of IL-10, since neutralizing anti-IL-10 antibodies reversed this inhibition to some extent. The EMSA of the NF-kappaB site in the IL-15 promoter showed that PGE2 inhibited binding of NF-kappaB in a dose dependent manner. Experiments using inducers and an inhibitor of cyclic AMP (cAMP) suggest that a major intracellular signal mediates the regulatory effect of PGE2 on the production of IL-15 and IL-10. CONCLUSION: PGE2 differentially regulates the production of IL-15 and IL-10 in FLS. The strong inhibition of PGE2 on IL-15 production is exerted via a cAMP-dependent modulation of NF-kappaB activity. Our data suggest that overproduced PGE2 in RA joints may play an antiinflammatory role.