• Bulletin of the Korean Chemical Society
• /
• v.34 no.6
• /
• pp.1637-1642
• /
• 2013

We carried out the melt copolymerization reactions of 1,2-bis(diethylamino)tetramethyldisilane with several aryldiols such as, 4,4'-biphenol, 4,4'-isopropylidenediphenol, 9H-fluoren-9,9-dimethanol, and 4,4'-(9-fluorenylidene) bis(2-phenoxyethanol) to afford poly[oxy(arylene)oxy(tetramethyldisilylene)]s containing fluorescent aromatic chromophore groups in the polymer main chain: poly[oxy(4,4'-biphenylene)oxy(tetramethyldisilylene)], poly[oxy{(4,4'-isopropylidene) diphenylene}oxy(tetramethyldisilylene)], poly[oxy(9H-fluorene-9,9-dimethylene) oxy(tetramethyldisilylene)], and poly[oxy{4,4'-(9-fluorenylidene)bis(2-phenoxyethylene)}oxy(tetramethyldisilnylene)]. These prepared materials are soluble in common organic solvents such as $CHCl_3$ and THF. The obtained polymers were characterized by several spectroscopic methods such as $^1H$, $^{13}C$, and $^{29}Si$ NMR. Further, FTIR spectra of all the polymers exhibited characteristic Si-O stretching frequencies at 1014-1087 $cm^{-1}$. These polymeric materials in THF showed strong maximum absorption peaks at 268-281 nm, strong maximum excitation peaks at 263-291 nm, and strong maximum fluorescence emission bands at 314-362 nm due to the presence of tetramethyldisilylene and several arylene chromophores in the polymer main chain. TGA thermograms indicated that most of the polymers were stable up to $200^{\circ}C$ with a weight loss of 3-16% in nitrogen.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.4
• /
• pp.1303-1309
• /
• 2011

Melt copolymerization reactions of bis(diethylamino)tetramethyldisiloxane with several aryldiols were carried out to afford poly(carbotetramethyldisiloxane)s containing fluorescent aromatic chromophore groups in the polymer main chain: poly{oxy(4,4'-biphenylene)oxytetramethyldisiloxane}, poly{oxy(1,4-phenylene)oxytetramethyldisiloxane}, poly[oxy{(4,4'-isopropylidene)diphenylene}oxytetramethyldisiloxane], poly[oxy{(4,4'-hexafluoroisopropylidene)diphenylene}oxytetramethyldisiloxane], poly{oxy(2,6-naphthalene)oxytetramethyldisiloxane}, poly[oxy{4,4'-(9-fluorenylidene)diphenylene}oxytetramethyldisiloxane], poly{oxy(fluorene-9,9-dimethylene)oxytetramethyldisiloxane}, and poly[oxy{4,4'-(9-fluorenylidene)bis(2-phenoxyethylene)}oxytetramethyldisiloxane]. These materials are soluble in common organic solvents such as $CHCl_3$ and THF. The FTIR spectra of all the polymers exhibit the characteristic Si-O-C stretching frequencies at 1021-1082 $cm^{-1}$. In the THF solution, the polymeric materials show strong maximum absorption peaks at 215-311 nm, with strong maximum excitation peaks at 250-310 nm, and strong maximum fluorescence emission bands at 310-360 nm. TGA thermograms indicate that most of the polymers are stable up to $200^{\circ}C$ with a weight loss of less than 10% in nitrogen.

• BMB Reports
• /
• v.43 no.6
• /
• pp.419-426
• /
• 2010

Aeromonas hydrophila is a bacterial pathogen that infects a large number of eukaryotes, including humans. The UDP-galactose 4'-epimerase (GalE) catalyzes interconversion of UDP-galactose to UDP-glucose and plays a key role in lipopolysaccharide biosynthesis. This makes it an important virulence determinant, and therefore a potential drug target. Our earlier studies revealed that unlike other GalEs, GalE of A. hydrophila exists as a monomer. This uniqueness necessitated elucidation of its structure and active site. Chemical modification of the 6xHis-rGalE demonstrated the role of histidine residue in catalysis and that it did not constitute the substrate binding pocket. Loss of the 6xHis-rGalE activity and coenzyme fluorescence with thiol modifying reagents established the role of two distinct vicinal thiols in catalysis. Chemical modification studies revealed arginine to be essential for catalysis. Site-directed mutagenesis indicated Tyr149 and Lys153 to be involved in catalysis. Use of glycerol as a cosolvent enhanced the GalE thermostability significantly.

• Molecular & Cellular Toxicology
• /
• v.5 no.2
• /
• pp.108-112
• /
• 2009

Alzheimer's disease(AD) is a neurodegenerative disorder characterized pathologically by senile plaques, neurofibrillary tangles, and synapse loss. Especially, extracellular beta-amyloid (Abeta) deposition is a major pathological hallmark of Alzheimer's disease (AD). In AD senile plaques, high level of iron and car-bonylated Abeta were detected. Iron has a Lewis acid property which can increase the electrophilicity of carbonyls, which may react catalytically with nucleophiles, such as amines. Hence, this study investigated whether or not iron could promote the carbonylation of amine with malondialdehyde (MDA) in the physiological condition. As the basic study, we examined that iron might promote the conjugation reaction between propylamine, monoamine molecule and MDA in the physiological condition. As the concentration of iron increased, the fluorescence intensity produced from the conjugation reaction increased in a dose-dependent manner. Instead of propylamine, we applied the same reaction condition to Abeta 1-40 peptide, one of major components founded in AD senile plaques for the conjugation reaction. As the result, the fluorescence intensity produced from the conjugation reaction between Abeta 1-40 peptide and MDA showed the similar trend to that of the reaction used with propylamine. This study suggests that iron can accelerate the conjugation reaction of MDA to Abeta 1-40 peptide and play an another important role in deterioration of AD brain.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1995.04a
• /
• pp.75-75
• /
• 1995

Succinic semialdehyde reductase, one of key enzyme of GABA shunt in CNS, is inactivated by o-phthalaldehyde, The inactivation followed pseudo first-order kinetics, and the second-order rate constant for the inactivation process was 28 M$\^$-1/s$\^$-1/ at pH 7.4 and 25$^{\circ}C$. The absorption spectrum(λ$\_$max/=377nm), fluorescence exitation(λ$\_$max/=340nm) and fluorescence emission spectra (λ$\_$max/=409nm) were consistent with the formation of an isoindole derivative in the catalytic site between a cysteine and a lysine residues about 3${\AA}$ apart. The substrate, succinic semialdehyde, did not protect the enzymatic activity against inactivation, whereas the coenzyme, NADPH, protected against o-phthalaldehyde induced inactivation of the enzyme. About 1 isoindole group per moi of the enzyme was formed following complete loss of the enzymatic activity. These results suggest that the amino acid residues of the enzyme participating in reaction with o-phthalaldehyde more likely residues at or near the coenzyme binding site.

• Clinical and Experimental Pediatrics
• /
• v.59 no.sup1
• /
• pp.14-18
• /
• 2016

Pediatric epilepsy can be caused by various conditions, including specific syndromes. 1p36 deletion syndrome is reported in 1 in 5,000-10,000 newborns, and its characteristic clinical features include developmental delay, mental retardation, hypotonia, congenital heart defects, seizure, and facial dysmorphism. However, detection of the terminal deletion in chromosome 1p by conventional G-banded karyotyping is difficult. Here we present a case of epilepsy with profound developmental delay and characteristic phenotypes. A 7-year-and 6-month-old boy experienced afebrile generalized seizure at the age of 5 years and 3 months. He had recurrent febrile seizures since 12 months of age and showed severe global developmental delay, remarkable hypotonia, short stature, and dysmorphic features such as microcephaly; small, low-set ears; dark, straight eyebrows; deep-set eyes; flat nasal bridge; midface hypoplasia; and a small, pointed chin. Previous diagnostic work-up, including conventional chromosomal analysis, revealed no definite causes. However, array-comparative genomic hybridization analysis revealed 1p36 deletion syndrome with a 9.15-Mb copy loss of the 1p36.33-1p36.22 region, and fluorescence in situ hybridization analysis (FISH) confirmed this diagnosis. This case highlights the need to consider detailed chromosomal study for patients with delayed development and epilepsy. Furthermore, 1p36 deletion syndrome should be considered for patients presenting seizure and moderate-to-severe developmental delay, particularly if the patient exhibits dysmorphic features, short stature, and hypotonia.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 1998.07a
• /
• pp.12-18
• /
• 1998

Tremendous progress has been made over the past quarter-century studying the genetics of gametogenesis and the resulting gametes and embryos. Studies merging molecular techniques and conventional cytogenetics are now beginning to bridge the gap between what we have learned about the meiotic process in males and females and what we know of the mitotic chromosomes of zygotes. Numerical abnormalities in sperm, oocytes and embryo can now diagnosed by fluorescence in situ hybridization (FISH). "At risk" couples can, therefore, have only unaffected embryos replaced in the sterus and avoid the possibility of terminating a pregnancy that might only be diagnosed as affected later gestation. Single-cell genetic analysis has also provided powerful tools for studying genetic defects arising during early human development. Recent studies of sperms, oocytes and cleavage-stage human embryos have revealed an unexpectedly high incidence. These genetic abnormalities are likely to contribute to early pregnancy loss and have important implications for improving pregnancy rates in infertile couples by assisted reproduction. The widespread use of preimplantation genetic diagnosis (PGD) awaits further documentatio of safety and accuracy. Other issues also must be addressed. First, the ethical issues regarding germ cell and embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for non-genetic disorders such as gender selection. Finally, the experimental nature of these procedure must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved assisted reproductive technology success rates may make PGD a more widely use clinical tool. The future awaits these development.velopment.

• Journal of Sericultural and Entomological Science
• /
• v.51 no.2
• /
• pp.142-146
• /
• 2013

The fluorescent proteins are generally denatured by heat treatment and thus lose their color. The normal reeling method includes processing by drying and cooking the cocoons near $100^{\circ}C$ before reeling. Therefore, the usual processing method cannot be used for making colored fluorescent silks. To develop a method that is applicable to producing transgenic silk without color loss, we develop reeling methods adequate for a recombinant fluorescence cocoons. It was found that the fluorescence cocoons keep their native color when dried at temperatures lower than $60^{\circ}C$ for 15 h. Also, a new cooking method to soften the fluorescent cocoons was developed: the cocoons were soaked in a solution of 0.2% sodium carbonate ($Na_2CO_3$)/0.1% nonionic surfactant (Triton X100) at $60^{\circ}C$ and then placed under vacuum. The repeated vacuum treatments enabled complete penetration of the solution into the cocoons, and the cocoons were thus homogenously softened and ready for reeling. In this state, the cooked cocoons can be reeled by an automated reeling machine. Our results suggest that drying and cooking of the cocoons at low temperature enables the subsequent reeling of the colored fluorescent silks by an automatic reeling machine without color loss and can produce silks that can be used for making higher value-added silk materials.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.36 no.3
• /
• pp.215-219
• /
• 2010

In this study, we investigated effects of Monegy (mixture of Sophorae Radix, Panax ginseng, Salvia miltiorrhiza BUNGE) on epilate-induced hair-loss in dorsal region of C57/BL6 mice and external structure of human hair. For morphological and histological analysis in scalp of epilate-induced hair-loss animal model, we utilized several microscopic techniques, such as confocal laser scanning microscopy (CLSM) and LAS 4000. Confocal analysis showed the distribution of FITC-conjugated Monegy and penetration depth compared with normal and control group. Furthermore, when Monegy was topically administrated onto a C57BL6 mouse, it penetrated very well. The fluorescence intensity was increased upto 205 and 113 folds compared to normal and control group, respectively. Also, area of fluorescence was increased to upto 255 to 127 folds compared to normal and control group. Broad scale area of fluorescence in dermis region was observed in the Monegy-treated mice. Furthermore, Monegy induced upto 75% hair repair against depilation. It might be promoted via the induction of growth factors in hair follicle.

• Environmental Engineering Research
• /
• v.10 no.4
• /
• pp.181-190
• /
• 2005

Severe loss or hydrogen occurred in most anaerobic hydrogen fermentation reactors. Several selected methods were applied to suppress the consumption of hydrogen and increase the potential of production. As the first trial, pH shock was applied. The pH of reactor was dropped nearly to 3.0 by stopping alkalinity supply and on]y feeding glucose (5 g/L-d). As the pH was increase to $4.8{\pm}0.2,$ the degradation pathway was derived to solventogenesis resulting in disappearance of hydrogen in the headspace. In the aspect of bacterial community, methanogens weren't detected after 22 and 35 day, respectively. Even though, however, there was no methanogenic bacterium detected with fluorescence in-situ hybridization (FISH) method, hydrogen loss still occurred in the reactor showing a continuous increase of acetate when the pH was increased to $5.5{\pm}0.2$. This result was suggesting the possibility of the survival of spore fanning acetogenic bacteria enduring the severely acidic pH. As an alternative and additive method, nitrate was added in a batch experiment. It resulted in the increase of maximum hydrogen fraction from 29 (blank) to 61 % $(500\;mg\;NO_3/L)$. However, unfortunately, the loss of hydrogen occurred right after the depletion of nitrate by denitrification. In order to prevent the loss entangled with acetate formation, $CO_2$ scavenging in the headspace was applied to the hydrogen fermentation with heat-treated sludge since it was the primer of acetogenesis. As the $CO_2$ scavenging was applied, the maximum fraction of hydrogen was enhanced from 68 % to 87 %. And the loss of hydrogen could be protected effectively.