• Macromolecular Research
• /
• v.12 no.4
• /
• pp.367-373
• /
• 2004

We have developed a rigorous heat treatment method to improve the biocompatibility of chitosan as a tissue-engineered scaffold. The chitosan scaffold was prepared by the controlled freezing and lyophilizing method using dilute acetic acid and then it was heat-treated at 110$^{\circ}C$ in vacuo for 1-3 days. To explore changes in the physicochemical properties of the heat-treated scaffold, we analyzed the degree of deacetylation by colloid titration with poly(vinyl potassium sulfate) and the structural changes were analyzed by scanning electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffractometry (WAXD), and lysozyme susceptibility. The degree of deacetylation of chitosan scaffolds decreased significantly from 85 to 30% as the heat treatment time increased. FT-IR spectroscopic and WAXD data indicated the formation of amide bonds between the amino groups of chitosan and acetic acids carbonyl group, and of interchain hydrogen bonding between the carbonyl groups in the C-6 residues of chitosan and the N-acetyl groups. Our rigorous heat treatment method causes the scaffold to become more susceptible to lysozyme treatment. We performed further examinations of the changes in the biocompatibility of the chitosan scaffold after rigorous heat treatment by measuring the initial cell binding capacity and cell growth rate. Human dermal fibroblasts (HDFs) adhere and spread more effectively to the heat-treated chitosan than to the untreated sample. When the cell growth of the HDFs on the film or the scaffold was analyzed by an MTT assay, we found that rigorous heat treatment stimulated cell growth by 1.5∼1.95-fold relative to that of the untreated chitosan. We conclude that the rigorous dry heat treatment process increases the biocompatibility of the chitosan scaffold by decreasing the degree of deacetylation and by increasing cell attachment and growth.

• Journal of Ginseng Research
• /
• v.34 no.4
• /
• pp.369-375
• /
• 2010

This study evaluated the protective effects of ginseng leaf extract (GLE) against high fat-diet-induced hyperglycemia and hyperlipidemia, and explored the potential mechanism underlying these effects in C57BL/6J mice. The mice were randomly divided into four groups: normal control, high fat diet control (HFD), GLE-treated at 250 mg/kg, and GLE-treated at 500 mg/kg. To induce hyperglycemic and hyperlipidemic states, mice were fed a high fat diet for 6 weeks and then administered GLE once daily for 8 weeks. At the end of the treatment, we examined the effects of GLE on plasma glucose, lipid levels, and the expression of genes related to lipogenesis, lipolysis, and gluconeogenesis. Both GLE groups lowered levels of plasma glucose, insulin, triglycerides, total cholesterol, and non-esterified fatty acids when compared to those in HFD group. Histological analysis revealed significantly fewer lipid droplets in the livers of GLE-treated mice compared with HFD mice. To elucidate the mechanism, Western blots and RT-PCR were performed using liver tissue. Compared with HFD mice, GLE-treated mice showed higher levels of phosphorylation of AMP-activated protein kinase (AMPK) and its substrate, acetyl-CoA carboxylase, but no differences in the expression of lipogenic genes such as sterol regulatory element-binding protein 1a, fatty acid synthase, sterol-CoA desaturase 1 and glycerol-3-phosphate acyltransferase. However, the expression levels of lipolysis and fatty acid uptake genes such as peroxisome proliferator-activated receptor-$\alpha$ and CD36 were increased. In addition, phosphoenolpyruvate carboxykinase gene expression was decreased. These results suggest that GLE ameliorates hyperglycemia and hyperlipidemia by inhibiting gluconeogenesis and stimulating lipolysis, respectively, via AMPK activation.

• Molecules and Cells
• /
• v.19 no.3
• /
• pp.398-401
• /
• 2005

The bacterial enzyme UDP-N-acetylglucosamine enolpyruvyl transferase catalyzes the first committed step of peptidoglycan biosynthesis, i.e., transfer of enolpyruvate from phosphoenolpyruvate to UDP-N-acetyl-glucosamine. We have overexpressed the enzyme from Haemophilus influenzae in Escherichia coli and crystallized it in the apo-form, as well as in a complex with UDP-N-acetylglucosamine and fosfomycin using ammonium sulfate as the precipitant. X-ray diffraction data from a crystal of the apo-form were collected to $2.8{\AA}$ resolution at 293 K. The crystal quality was improved by co-crystallization with UDP-N-acetylglucosamine and fosfomycin. X-ray data to $2.2{\AA}$ have been collected at 100 K from a flash-frozen crystal of the complex. The complex crystals belong to the orthorhombic space group I222 (or $I2_12_12_1$) with unit-cell parameters of a = 63.7, b = 124.5, and $c=126.3{\AA}$. Assuming a monomer of the recombinant enzyme in the crystallographic asymmetric unit, the calculated Matthews parameter ($V_M$) is $2.71{\AA}^3Da^{-1}$ and solvent content is 54.6%.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
• /
• 2001.12a
• /
• pp.22-37
• /
• 2001

Melatonin is secreted during the hours of darkness and is thought to influence the circadian and seasonal timing of a variety of physiological processes. Serotonin N-acetyltransferase (AA-NAT) which is found to be expressed in pineal gland, retina, and various tissues, catalyses the conversion of serotonin to N-acetylserotonin and is known as the rate-limiting enzyme in the biosynthetic pathway of melatonin. The compounds that modulate the activity of AA-NAT can be used to treat serotonin-and melatonin-related diseases such as insomnia, depression and seasonal affective disorders (SAD). Several assay methods have been developed by which to measure AA-NAT activity. We have also developed a simple, rapid and sensitive AA-NAT assay method that takes advantage of differences in the organic solubilities between acetyl CoA and N-acetyltryptamine. We screened modulators of AA-NAT activity from the water extracts of the medicinal plants. We found MNP1005 which strongly inhibited the activity of AA-NAT ($IC_{50}$=2.2$\mu$M). Enzyme inhibitory kinetic studies revealed that MNP1005 exhibited a noncompetitive inhibition toward tryptamine. The antidepressant effect of MNP1005 was investigated on behavioral despair test so called forced swimming test (FST). MNP1005 significantly increased swimming behavior by reducing immobility with treatment of 10 mg/kg when compared to the vehicle-treated control group (P < 0.05). This suggests that MNP1005 possesses antidepressant activity. The influence of chronic MNP1005 treatment on the expression of brain-derived neurotrophic factor (BDNF) was examined by in situ hybridization and Northern blot. Chronic treatment of MNP1005 blocked the downregulation of BDNF mRNA in the frontal cortex and other cortex regions in response to restraint stress.

• Journal of Life Science
• /
• v.23 no.12
• /
• pp.1420-1427
• /
• 2013

A novel acetylalginate esterase (AcAlgE) gene was previously cloned and characterized from Sphingomonas sp. MJ-3. In this study, the synergistic effects of MJ-3 AcAlgE, and KS-408 alginate lyase on the degradation of acetylalginate from Pseudomonas aeruginosa were investigated by using high-field 1H-NMR and an FPLC-equipped peptide column. The alginate lyase coupled assay of AcAlgE showed that degradation of high molecular weight acetylalginate was more difficult than degradation of acid hydrolyzed acetylalginate. The degradation of acetylalginate by alginate lyase was easier after AcAlgE was used to remove the acetyl group from acetylalginate. This result showed that the recombinant AcAlgE enhanced the degradation of acetylalginate by alginate lyase.

• The Plant Pathology Journal
• /
• v.32 no.5
• /
• pp.407-413
• /
• 2016

Fusarium graminearum species complex (FGSC) causes Fusarium head blight in small grain cereals. To date, four species (F. graminearum, F. asiaticum, F. boothii, and F. meridionale ) belonging to FGSC frequently occur in Korean cereals. In addition, we first reported the occurrence of additional species (F. vorosii ) within FGSC, which was isolated from barley, corn, and rice in Korea. Phylogenetic analysis of the Fusarium isolates of this group using combined multigene sequences confirmed species identification. Moreover, the macroconidia produced by these isolates were morphologically similar to those of the F. vorosii holotype. Chemical analysis indicated that the F. vorosii isolates produced various trichothecenes such as nivalenol and deoxynivalenol with their acetyl derivatives along with zearalenone. Pathogenicity tests demonstrated that all of the F. vorosii isolates examined were pathogenic on barley, corn, and rice with variation in aggressiveness. This study is the first report of F. vorosii in Korean cereals, their pathogenicity towards barley and corn, and their ability to produce trichothecenes and zearalenone.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.6
• /
• pp.699-708
• /
• 2022

Antibiotic exposure during pregnancy have an adversely effects on offspring behavior and development. However, its mechanism is still poorly understood. To uncover this, we added ceftriaxone sodium to the drinking water of rats during pregnancy and conducted three-chamber sociability test, open-field test, and Morris water maze test in 3- and 6-week-old offspring. The antibiotic group offspring showed lower sociability and spatial learning and memory than control. To determine the role of the gut microbiota and their metabolites in the changes in offspring behavior, fecal samples of 6-week-old offspring rats were sequenced. The composition of dominant gut microbial taxa differed between the control and antibiotic groups. KEGG pathway analysis showed that S24-7 exerted its effects through the metabolic pathways including mineral absorption, protein digestion and absorption, Valine, leucine, and isoleucine biosynthesis. Correlation analysis showed that S24-7 abundance was negatively correlated with the level of VEGF, and metabolites associated with S24-7-including 3-aminobutanoic acid, dacarbazine, L-leucine, 3-ketosphinganine, 1-methylnicotinamide, and N-acetyl-L-glutamate-were also significantly correlated with VEGF levels. The findings suggest that antibiotic exposure during pregnancy, specifically ceftriaxone sodium, will adversely affects the behavior of offspring rats due to the imbalance of gut microbiota, especially S24-7, via VEGF and various metabolic pathways.

• The Korea Journal of Herbology
• /
• v.37 no.5
• /
• pp.17-26
• /
• 2022

Objective : The aim of the present study is to examine hepatic lipid-lowering and anti-inflammatory effects of silymarin combined with Jakyakgamcho-tang on non-alcoholic fatty liver disease in a high fat diet-induced obese mice model. Methods : C57BL/6 mice were divided into four dietary groups: (1) Normal, (2) Control (60% high-fat diet), (3) Control + silymarin 50 mg/kg/day (Silymarin), (4) Control + Silymarin 50 mg/kg/day + Jakyakgamcho-tang 100 mg/kg/day (SPG). After 12 weeks administration, mice were sacrificed and lipids and inflammation-related biomarkers were analyzed liver and plasma. Results : Silymarin and SPG treatments significantly lowered body and liver weights compared to the Control. Serumlipids (triglyceride (TG), total cholesterol) and pro-inflammatory cytokines (tumor necrosis factor alpha, interleukin 1𝛽, and IL-6) concentrations were significantly lowered in the Silymarin and SPG groups than the Control group. Silymarin and SPG treatments suppressed hepatic TG level and hepatic lipid droplets compared to the Control. Theses two treatments significantly increased hepatic kinase B1 and AMP-activated protein kinase protein levels, and significantly decreased hepatic key lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase and stearyl coenzyme A desaturase 1) protein levels than the Control. SPG also significantly increased hepatic fatty acid oxidation-related protein (peroxisome proliferator-activated receptor alpha and uncoupling protein 2) levels than the Control. Conclusions: Silymarin and SPG suppressed hepatic lipid accumulation by regulating hepatic protein expression, and lowered blood pro-inflammatory cytokines concentrations though the synergic effect of silymarin and Jakyakgamchotang was not clear.

• Fisheries and Aquatic Sciences
• /
• v.26 no.9
• /
• pp.535-547
• /
• 2023

Sea cucumbers (Holothuria scabra), also known as beche-de-mer, are highly valued as a luxurious food item and have been utilized as a traditional tonic food in various Asian countries for centuries. The body walls of sea cucumbers are the main edible part, which are primarily composed of glycosaminoglycan (GAG). The rehydration of dried sea cucumber is a crucial step prior to further processing. The aim of this study was to assess the impact of ultrasound-assisted rehydration (UAR) on the quality of dried sea cucumbers. The experiment used four different rehydration methods, including conventional methods at 27℃ (KV27℃) and 15℃ (KV15℃), as well as a combination of ultrasound at 27℃ with conventional at 15℃ (UAR27 + KV15℃) and ultrasound at 15℃ with conventional at 15℃ (UAR15 + KV15℃). Results indicated that the rehydration rate (RR) was significantly affected by both the rehydration method and the temperature used (p < 0.05). UAR27 + KV15℃ was identified as the most effective method in terms of rehydration behavior and quality characteristics of dried sea cucumber, with a RR of 0.58 ± 0.53 gH₂O/hour and reduced rehydration time of up to 28 hours. Moreover, the UAR27 + KV15℃ method demonstrated superior rehydration potential, nutritional value (proximate composition and sulfate content), color, lower energy, and microstructure properties compared to the other methods. The sulfate content and yield of sulfated GAGs were determined to be 89.4 mg/g and 52.8 ㎍/g, respectively. Confirmation of the absorption band of the sulfate group showed the presence of 3-N-acetyl galactosamine at a wavelength of 1,269 cm^-1 and C-O-S at 860 cm^-1. The sea cucumbers treated with UAR exhibited a GAG content approximately 2.9 times higher than those rehydrated with the conventional method. Eventually, the combination of UAR at 27℃ with conventional at 15℃ methods can significantly accelerate the rehydration of sea cucumber without negatively affecting its physical quality properties.

• Textile Coloration and Finishing
• /
• v.35 no.4
• /
• pp.239-245
• /
• 2023

Cellulose is an abundant biodegradable material in nature with excellent properties, but due to its poor processability, it has been widely studied for processing through modification. Cellulose acetate propionate (CAP) is a cellulose derivative in which the hydroxyl group of cellulose is replaced by acetyl and propionyl groups. CAP has several advantages, such as excellent solubility, structural stability, light and weather resistance, and good transparency. Porous nanofibers with excellent specific surface area, which can be applied in various fields, can be easily formed by the phase separation method using highly volatile solvents. High speed centrifugal spinning is a nano/micro fiber preparation method with advantages such as fast spinning and easy alignment control. In this study, a CAP/polybutylene succinate (PBS) spinning solution with chloroform as solvent was prepared to prepare porous microfibers and the fiber morphology was examined as a function of the disk rotation speed in an high speed centrifugal spinning device.