• Journal of Life Science
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• v.21 no.1
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• pp.127-133
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• 2011

${\beta}$-Galactosidase was immobilized on chitosan bead by covalent bonding using glutaraldehyde. The characteristics of the immobilized enzyme were investigated. Maximum immobilization yield of 75% was obtained on chitosan bead. Optimum pH and temperature for the immobilized enzyme was 7.0 and $50^{\circ}C$, respectively. The immobilized enzyme showed a broader range of pH and temperature compared to a free one. A mathematical model for the operation of the immobilized enzyme in a packed-bed reactor was established and solved numerically. Under different inlet lactose concentrations and feed flow rate conditions, lactose conversion was measured in a packed-bed reactor. The experimental results of continuous operation in a packed-bed reactor were compared to theoretic results using Michaelis-Menten kinetics with competitive product inhibition and external mass transfer resistance. The model predicted the experimental data with errors less than 5%. Process optimization of continuous operation in a packed-bed reactor was also conducted. In a recirculation packed-bed operation, conversion of lactose was 97% in 3 hours. In a continuous packed-bed operation, the effect of flow rate and initial lactose concentration was investigated. Increasing flow rates and initial lactose concentration decreased the conversion of substrate.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.246-252
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• 2016

Objectives: The purpose of this study was to obtain a natural antibiotic from Phenol-rich compounds; for the dressing and the treatment of chronic wounds. Methods: The Phenol-rich compound sweet gel was prepared by blending four natural herbal extracts, Acacia catechu (L.F.), Momia (Shilajit), Castanea sativa, and Ephedra sinica stapf, with combination of a sweet gel medium, including honey, maple saps, Phoenix dactylifera L. (date), pomegranate extract and Azadirachta indica gum as a stabilizer. The combinations were screened by using a well-diffusion assay with cloxacillin as a control. Pseudomonas spp. was tested with our novel antimicrobial compound. The zones of inhibition in agar culture were measured for each individual component and for the compound, and the results were compared with those of the control group which had been treated with cloxacillin. Data were expressed as means ${\pm}$ standard deviations. Quantitative analyses were performed using the paired t-test. Results: The antibiotic effect of the Phenol-rich compound sweet gel was statistically shown to be more significant than that of cloxacillin against Pseudomonas aeruginosa (P < 0.05). Conclusion: Our novel approach to fighting the antibiotic resistance of Pseudomonas proved to be successful. The Phenol-rich compound sweet gel was found to be suitable for use as an alternative medicine and bioactive dressing material, for the treatment of patients with various types of wounds, including burns, venous leg ulcers, ulcers of various etiologies, leg ulcers on the feet of diabetic, unhealed graft sampling sites, abscesses, boils, surgical wounds, necrotic process, post-operative and neonatal wound infection, and should be considered as an alternative to the usual methods of cure.

• Korean Journal of Microbiology
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• v.6 no.4
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• pp.122-130
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• 1968

Action of various wavelengths of visible light on ultraviolet-radiation damage to haploid yeast cells, Saccharomyces cerevisiae 23971, was studied. The results were obtained on the basis of the survival and respiration rates by pre- and post-illuminations of various wavelengths before and after U.V.-irradiations on the yeast cells. Among the wavelengths tested, 635 $m{\mu}$, 429 $m{\mu}$ and white light which caused increase of respiration in pre-treatment alone, induced less resistance to the U. V.-damage than in the control, in both pre- and U.V.-treatment. On the contrary, such wavelengths as 574 $m{\mu}$and 530 $m{\mu}$, showing a weak effect on respiration in pre-treatment increased the susceptability to U.V.-radiation. Photoinactivation was generally obtained by both pre- and post- illuminations along with U.V.-treatment. At 635 $m{\mu}$ the PI rate was the lowest and also a low PI rate was shown at 429 $m{\mu}$. But 429 $m{\mu}$, in the post-treatment of the yeast cells pre-treated by the white light and the darkness respectively, showed the highest PI rate. In both pre- and post- treatment of 574, 530 and 473 $m{\mu}$,the PI rates were high to the same degree. Post-treatments of the wavelengths on U.V.-treated yeasts incubated rather under the white light than the darkness induced lower PI rate. It is assumed that there are great differences in action even of the same wavelength, depending upon the various combination of pre- and post-treatments, and that, moreover, the action of various wavelengths of visible light on U.V.-damage on the cells are concerned with the doses and dose rates of U.V. and visible lights. These observations led to an interpretation that each wavelength of visible light might exert distinctively different effects oil U. V.-damage, mainly causing the inhibition or stimulation of enzymes in the yeast cells.

• Journal of Microbiology
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• v.45 no.4
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• pp.318-325
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• 2007

Glucose 6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) in Deinococcus radiophilus, an extraordinarily UV-resistant bacterium, was investigated to gain insight into its resistance as it was shown to be involved in a scavenging system of superoxide $(O_2^{-1})$ and peroxide $(O_2^{-2})$ generated by UV and oxidative stresses. D. radiophilus possesses two G6PDH isoforms: G6PDH-1 and G6PDH-2, both showing dual coenzyme specificity for NAD and NADP. Both enzymes were detected throughout the growth phase; however, the substantial increase in G6PDH-1 observed at stationary phase or as the results of external oxidative stress indicates that this enzyme is inducible under stressful environmental conditions. The G6PDH-1 and G6PDH-2 were purified 122- and 44-fold (using NADP as cofactor), respectively. The purified G6PDH-1 and G6PDH-2 had the specific activity of 2,890 and 1,033 U/mg protein (using NADP as cofactor) and 3,078 and 1,076 U/mg protein (using NAD as cofactor), respectively. The isoforms also evidenced distinct structures; G6PDH-1 was a tetramer of 35 kDa subunits, whereas G6PDH-2 was a dimer of 60kDa subunits. The pIs of G6PDH-1 and G6PDH-2 were 6.4 and 5.7, respectively. Both G6PDH-1 and G6PDH-2 were inhibited by both ATP and oleic acid, but G6PDH-1 was found to be more susceptible to oleic acid than G6PDH-2. The profound inhibition of both enzymes by ${\beta}-naphthoquinone-4-sulfonic$ acid suggests the involvement of lysine at their active sites. $Cu^{2+}$ was a potent inhibitor to G6PDH-2, but a lesser degree to G6PDH-1. Both G6PDH-1 and G6PDH-2 showed an optimum activity at pH 8.0 and $30^{\circ}C$.

• Preventive Nutrition and Food Science
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• v.19 no.4
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• pp.247-260
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• 2014

The impact of folate on health and disease, particularly pregnancy complications and congenital malformations, has been extensively studied. Mandatory folic acid fortification therefore has been implemented in multiple countries, resulting in a reduction in the occurrence of neural tube defects. However, emerging evidence suggests increased folate intake may also be associated with unexpected adverse effects. This literature review focuses on contemporary issues of concern, and possible underlying mechanisms as well as giving consideration the future direction of mandatory folic acid fortification. Folate fortification has been associated with the presence of unmetabolized folic acid (PteGlu) in blood, masking of vitamin $B_{12}$ deficiency, increased dosage for anti-cancer medication, photo-catalysis of PteGlu leading to potential genotoxicity, and a role in the pathoaetiology of colorectal cancer. Increased folate intake has also been associated with twin birth and insulin resistance in offspring, and altered epigenetic mechanisms of inheritance. Although limited data exists to elucidate potential mechanisms underlying these issues, elevated blood folate level due to the excess use of PteGlu without consideration of an individual's specific phenotypic traits (e.g. genetic background and undiagnosed disease) may be relevant. Additionally, the accumulation of unmetabolized PteGlu may lead to inhibition of dihydrofolate reductase and other enzymes. Concerns notwithstanding, folic acid fortification has achieved enormous advances in public health. It therefore seems prudent to target and carefully monitor high risk groups, and to conduct well focused further research to better understand and to minimize any risk of mandatory folic acid fortification.

• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1299-1306
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• 2015

This study aims to investigate the mechanism of action of the cinnamon bark essential oil (CB), when used singly and also in combination with piperacillin, for its antimicrobial and synergistic activity against beta-lactamase TEM-1 plasmid-conferred Escherichia coli J53 R1. Viable count of bacteria for this combination of essential oil and antibiotic showed a complete killing profile at 20 h and further confirmed its synergistic effect by reducing the bacteria cell numbers. Analysis on the stability of treated cultures for cell membrane permeability by CB when tested against sodium dodecyl sulfate revealed that the bacterial cell membrane was disrupted by the essential oil. Scanning electron microscopy observation and bacterial surface charge measurement also revealed that CB causes irreversible membrane damage and reduces the bacterial surface charge. In addition, bioluminescence expression of Escherichia coli [pSB1075] and E. coli [pSB401] by CB showed reduction, indicating the possibility of the presence of quorum sensing (QS) inhibitors. Gas-chromatography and mass spectrometry of the essential oil of Cinnamomum verum showed that trans-cinnamaldehyde (72.81%), benzyl alcohol (12.5%), and eugenol (6.57%) were the major components in the essential oil. From this study, CB has the potential to reverse E. coli J53 R1 resistance to piperacillin through two pathways; modification in the permeability of the outer membrane or bacterial QS inhibition.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.5
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• pp.235-242
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• 2006

Cortical malformation-associated epileptic seizures are resistant to conventional anticonvulsant drugs. Relatively little research has been conducted on the effects of antiepileptic drugs (AEDs) on seizure activity in a rat model of dysplasia. We have used rats exposed to methylazoxymethanol acetate (MAM) in utero, an animal model featuring nodular heterotopia, to investigate the effects of ethosuximide (ETX) in the dysplastic brain. Pilocarpine was used to induce acute seizure in MAM-exposed and age-matched vehicle-injected control animals. Field potential recordings were used to monitor the amplitude and number of population spikes, and paired pulse inhibition in response to stimulation of the commissural pathway. Pharmaco-resistance was tested by measuring seizure latencies after pilocarpine administration (320 mg/kg, Lp.) with and without pre-treatment with ETX. Pre-treatment with 300 mg of ETX significantly prolonged the latency to the status epilepticus (SE) in both control and MAM-treated groups. Pre-treatment with ETX 100mg and ETX 200 mg had little effect in MAMexposed rats. However, ETX 200 mg prolonged the latency to the SE in control groups. Spontaneous field potential and secondary after-discharges were higher for MAM-treated rat in comparison with control rats injects with ETX. The main findings of this study are that acute seizures initiated in MAM-exposed rats are relatively resistant to standard ETX assessed in vivo. These data suggest that ETX do not prolong seizure latencies in MAM-rats exposed to pilocarpine.

• Molecules and Cells
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• v.43 no.9
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• pp.793-803
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• 2020

Myeloid-derived suppressor cells (MDSCs) promote tumour progression by contributing to angiogenesis, immunosuppression, and immunotherapy resistance. Although recent studies have shown that microRNAs (miRNAs) can promote the expansion of MDSCs in the tumour environment, the mechanisms involved in this process are largely unknown. Here, we report that microRNA 449c (miR-449c) expression was upregulated in myeloid progenitor cells upon activation of C-X-C motif chemokine receptor 2 (CXCR2) under tumour conditions. MiR-449c upregulation increased the generation of monocytic MDSCs (mo-MDSCs). The increased expression of miR-449c could target STAT6 mRNA in myeloid progenitor cells to shift the differentiation balance of myeloid progenitor cells and lead to an enhancement of the mo-MDSCs population in the tumour environment. Thus, our results demonstrate that the miR-449c/STAT6 axis is involved in the expansion of mo-MDSCs from myeloid progenitor cells upon activation of CXCR2, and thus, inhibition of miR-449c/STAT6 signalling may help to attenuate tumour progression.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.543-547
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• 2007

Bovine mastitis is costly infectious disease of dairy cattle, being responsible for significant economic losses all over the world. Also, mastitis has troubled about resistance to antibiotics. The purpose of this study was to screen a novel antimicrobial strain from various sources (raw milk and feeds (from farm of Paju, Dangjin, and Hwasung), commercial milk, Korean traditional fermented foods, and chicken feces). The isolate was screened using triple agar layer method and deferred method was used for confirmation of antimicrobial effect. Seventy six of isolates were screened using triple agar layer method. In these strain, 42 isolates were shown a broad spectrum of autimicrobial activity against mastitis pathogens. Especially, fourteen isolates were shown over 20 mm inhibition zone against S. aureous ATCC 25923. These results suggest that these novel antimicrobial strains could be used for the alternative of antibiotics.

• Nutrition Research and Practice
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• v.10 no.1
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• pp.42-48
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• 2016

BACKGROUND/OBJECTIVES: Seaweeds have been reported to have various health beneficial effects. In this study, we investigated the potential anti-obesity and anti-inflammatory effects of four types of domestic brown seaweeds in a high-fat diet-induced obese mouse model and bone marrow-derived macrophages (BMDM). MATERIALS/METHODS: Male C57BL/6N mice were fed low-fat diet (LFD), high-fat diet (HFD) or HFD containing Undaria Pinnatifida, HFD containing Laminaria Japonica (LJ), HFD containing Sargassum Fulvellum, or HFD containing Hizikia Fusiforme (HF) for 16 weeks. RESULTS: Brown seaweed supplementation did not affect long-term HFD-associated changes in body weight or adiposity, although mice fed HFD + LJ or HFD + HF gained slightly less body weight compared with those fed HFD at the beginning of feeding. Despite being obese, mice fed HFD + LJ appeared to show improved insulin sensitivity compared to mice fed HFD. Consistently, we observed significantly reduced blood glucose concentrations in mice fed HFD + LJ compared with those of mice fed HFD. Although no significant differences in adipocyte size were detected among the HFD-fed groups, consumption of seaweeds decreased formation of HFD-induced crown-like structures in gonadal adipose tissue as well as plasma inflammatory cytokines. BMDM from mice fed HFDs with seaweeds showed differential regulation of pro-inflammatory cytokines such as IL-$1{\beta}$ and IL-6 compared with BMDM from mice fed HFD by LPS stimulation. CONCLUSION: Although seaweed consumption did not prevent long-term HFD-induced obesity in C57BL/6N mice, it reduced insulin resistance (IR) and circulation of pro-inflammatory cytokines. Therefore, seaweeds may ameliorate systemic inflammation and IR in obesity partially due to inhibition of inflammatory signaling in adipose tissue cells as well as bone marrow-derived immune cells.