• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.262-266
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• 2000

The polymerase chain reaction was used to selectively detect sequences within the fimbrial antigen of Salmonella enteritidis. Sterile milk was artificially inoculated with known amount of S. enteritidis and then DNA was extracted with guanidine thiocyanate/phenol/chloroform, followed by PCR. A detection limit of as few as 100 colony forming unit (cfu) per 0.5 ml milk was obtained with this method. For the whole procedure, it took only 5 h. A semi-quantitative polymerase chain reaction assay which allows an estimation of colony forming unit of S. enteritidis was developed. Known amount of standard plasmid pGem-4Z-Sef B(-) containing cloned S. enteritidis fimbrial antigen gene was co-amplified with Salmonella genomic DNA isolated from artificially inoculated milk. The same set of primers were used for the amplification and the products were cleaved with Bam HI. The concentration of the target DNA could be estimated by comparing the intensity of the two bands after electrophoresis. The PCR-based protocol described in this paper provides a rapid, simple, and sensitive method for detecting S. enteritidis in milk.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.161-168
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• 1986

A 1.95Kb Sau3Al fragment coding for $\alpha$-amylase from Bacillus amyloliquefaciens was isolated by the shotgun method using Escherichia coli as a host. The genome of Bacillus amyloliquefaciens was partially digested with the restriction endonuclease Sau3Al and joined to plasmid YRp7 cleaved with the restriction endonuclease BamHI. The $\alpha$-amylase gene present in a 1.95Kb insert was stably maintained and expressed in Escherichia coli. The amount of $\alpha$-amylase activity produced by Escherichia coli containing the hybrid plasmid pEA24 was about 65% of the activity produced by the donor Bacillus amyloliquefaciens strain. The properties of $\alpha$-amylase produced by Escherichia coli were very similar to those produced by Bacillus amyloliquefaciens as based on optimum temperature, pH, and effect of CaCl$_2$ concentration. About 70% of the $\alpha$-amylase produced by Escherichia coli was localized in the periplasmic space, whereas the remaining enzyme was localized in the inner part of the cell.

• Journal of Nutrition and Health
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• v.33 no.6
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• pp.660-667
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• 2000

Previous studies on the effect of age on intestinal taurine transport in animals have invariably shown a decline in the activity of the transport system with increasing age. In the present study changes in taurine transporter activity were observed during cell differentiation in the human colon carcinoma cell line HT-29 This cell line exhibits various enterocytic characteristics when differentiated and therefore has frequently been used to study the characteristcs and regulation of nutrient and drug absorption in the small intestine at the cellular level. Pre-treatment of the cells with $\beta$-alanine(10mM) reduced the taurine transport activity to 33% of the value for the control cells(p<0.05) which implies that taurine and $\beta$-alanine share a common $\beta$-amino acid transport system for their celluar uptake in the HI-29 was continued until 21 days post seeding. Kinetic studies of the taurine transporter were conducted in the HT-29 cell line with varying taurine concentration(5-60$\mu$M) in the uptake medium Both Vmax and the Michaelis-Menten constant(Km) of taurine transporter were decreased as differentiation of the HT-29 cell line was progressed ; Vmax of the taurine transporter in cells incubated for 4, 14 and 21 days post seeding was 2.79$\pm$3.4m 16.89$\pm$1.74, and 0.85$\pm$0.08 and 0.32$\pm$0.01nmol.mg protein-1 .30min-1 respectively(p<0.001) and Km was 42.3$\pm$3.4, 16.89$\pm$1.74, and 11.2$\pm$3.0$\mu$M respectively (p<0.01) These results indicate that the activity of sodium dependent active taurine transport system in the HT-29 cell line is decreased as confluent cells are differentiated. This phenomenon in cell culture system corresponds well with the earlier observation of lower intestinal taurine transport activity in suckling rats compared to that in adult animals although direct relationship of cell differentiation with in vivo aging process needs further verification.

• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1120-1127
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• 2017

Marasmius scorodonius secretes an extracellular laccase in potato dextrose broth, and this enzyme was purified up to 206-fold using $(NH_4)_2SO_4$ precipitation and a Hi-trap Q Sepharose column. The molecular mass of the purified laccase was estimated to be ~67 kDa by SDS-PAGE. The UV/vis spectrum of the enzyme was nontypical for laccases, and metal content analysis revealed that the enzyme contains 1 mole of Fe and Zn and 2 moles of Cu per mole of protein. The optimal pH for the enzymatic activity was 3.4, 4.0, and 4.6 with 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonate) (ABTS), guaiacol, and 2,6-dimethoxy phenol as the substrate, respectively. The optimal temperature of the enzyme was $75^{\circ}C$ with ABTS as the substrate. The enzyme was stable in the presence of some metal ions such as $Ca^{2+}$, $Cu^{2+}$, $Ni^{2+}$, $Mg^{2+}$, $Mn^{2+}$, $Ba^{2+}$, $Co^{2+}$, and $Zn^{2+}$ at a low concentration (1 mM), whereas $Fe^{2+}$ completely inhibited the enzymatic activity. The enzymatic reaction was strongly inhibited by metal chelators and thiol compounds except for EDTA. This enzyme directly decolorized Congo red, Malachite green, Crystal violet, and Methylene green dyes at various decolorization rates of 63-90%. In the presence of 1-hydroxybenzotriazole as a redox mediator, the decolorization of Reactive orange 16 and Remazol brilliant blue R was also achieved.

• Nutritional Sciences
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• v.8 no.3
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• pp.159-168
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• 2005

Phytoestrogens, especially Yak-kong or soybean-derived isoflavones have been traditionally used as a supplement of estrogen for preventing postmemopausal osteoporosis in oriental folk medicine. In our previous study, the treatment of Yak-kong and soybean increased estrogen receptor-a (ERa) expression and proliferation of MG-63 osteoblastic cells. In contrast, the increase of estrogen receptor-$\beta$ (ER$\beta$) expression in proliferating MG-63 cells with Yak-kong and soybean treatment was less pronounced, which suggested that ER$\beta$ may play a role rather in the regulation of bone cell differentiation To determine the role of ER$\beta$ in Yak-kong or soybean mediated regulation of bone cell differentiation, we established MG-63 cell lines stably expressing either ER$\beta$ or antisense ER$\beta$ RNAs. Increased expression of ER$\beta$ did not affect ERa expression and proliferation of MG-63 cells. However, increased expression of ER$\beta$ in MG-63 cells (ER$\beta$-MG63 cells) selectively enhanced Yak-kong or soybean induced expression of osteoprotegerin (OPG), a novel soluble glycoprotein which is secreted from osteoblasts and mediates the signal for osteoclast differentiation. Inhibition of ER$\beta$ expression by antisense ER$\beta$ RNAs (As-ER$\beta$-MG63) caused these cells to insensitize Yak-kong or soybean induced expression of OPG but increased MG-63 cell proliferation. Furthermore, the comparable effects between Yak-kong and the combined treatment of genistein and daidzein at $0.5{\times}l0^{-8}$ M, which is a concentration of these two isoflavones similar to Yak-kong at 0.001 mg/mL, on OPG expression in ER$\beta$-MG63 cell demonstrate that the enhanced expression of OPG with Yak-kong treatment is mediated by the synergistic effect of low leveled isoflavones in the extracts. Together, coupled with low level of ER expression in osteoclasts, our data demonstrate that ER$\beta$ in osteoblasts plays an important role in Yak-kong and soybean mediated inhibition of osteoclast differentiation indirectly by enhancing the expression of OPG.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.237-244
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• 1993

The effect of nicotine on the secretion of $[Met^{5}]-enkephalin$ (ME) in addition to proenkephalin A (proENK) mRNA levels and effects of indomethacin, nordihydroguaiaretic acid (NDGA), and captopril on nicotine-induced responses were studied in bovine adrenal medullary chromaffrin (BAMC) cells. Long-term exposure of BAMC cells to nicotine at a concentration of $10{\mu}M$ significantly increased proENK mRNA level and the secretion of ME into the medium. Treatment of BAMC cells with NDGA (a lipoxygenase inhibitor, $10{\mu}M$), indomethacin (a cycloooxygenase inhibitor) or captopril (an angiotensin converting enzyme inhibitor) alone did not affect ME secretion and proENK mRNA levels. The pretreatment of BAMC cells with NDGA inhibited the increased ME secretion and proENK mRNA level induced by nicotine. However, indomethacin and captopril did not affect nicotine-induced responses. Our results indicate that neuronal regulations of ME secretion and proENK mRNA level induced by nicotine in BAMC cells are in part mediated by a lipoxygenase-but not cyclooxygenase-and endogenous renin-angiotensin pathway.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.3 s.31
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• pp.55-59
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• 2006

Objective : This experimental study was performed to investigate the contents of glucan from mycellium and its activity against methicillin-resistant Staphylococcus(MRSA). Methods : A gel permeation chromatography method was develped for the determination and isolation of glucan in mycellium. Their structures were elucidated using ^1H-NMR$, ^{13}C-NMR$. Also, The antibacterial activity of the glucan against MRSA was estimathed by determining the minimum inhibitory concentration(MIC). Results : The contents of glucan in mycellium was $766{\pm}0.19$ mg/g. Glucan exhibited activity against MRSA, with an MIC values of 4 to 9 mg/mL. Conclusions : These findings suggested that glucan might be useful in controlling MRSA infections.

• Korean Journal of Pharmacognosy
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• v.26 no.4
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• pp.349-354
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• 1995

Crude methanolic(80%) extracts from 109 kinds of traditional herbal drugs were randomly screened for inhibitory effects on 5-hydroxytryptamine(5-HT) uptake in primary cultured rat brainstem neurons. Rat brainstem neurons were cultured from embryonic day 14, and maintained for 7-9 days in vitro. Clomipramine (500 nM), a reference drug, decreased 5-HT uptake to 16% of control values. Of the 109 herbal drugs screened, Citri immaturi Pericarpium(靑皮), Coptidis Rhizoma(黃蓮), Cnidii Rhizoma(土川芎) showed the most potent 5-HT uptake inhibiting activities. These herbal drugs, at the concentration of $10{\;}{\mu}g/ml$, inhibited 5-HT uptake 69, 69, and 57% respectively, when inhibition(%) was expressed as a relative value compared to the 500 nM clomipramine-induced inhibition.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.67-84
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• 2005

This research was conducted to evaluate the effectiveness of reinforcement for nearly saturated soft clay compaction. The effectiveness was investigated by roller compaction test using nearly saturated clay specimens. The nearly saturated condition was obtained by submerging clay in the water for 12 hours. High water content specimens were compacted in plane strain condition by a steel roller. A specimen was compacted by four 5 cm horizontal layers. Specimens were prepared fur both reinforced and unreinforced cases to evaluate the effectiveness of reinforcement. Used reinforcement is a composite consisted of both woven and non-woven geotextile. The composite usually provides drainage and tensile reinforcement to hi인 water-contented clay so that it increases bearing capacity. Therefore, large compaction load can be applied to reinforced clay and it achieves higher density effectively. The reinforcement also increases compaction efficiency because it reduces the ratio between shear and vertical forces during compaction process. The maximum vertical stress on the base of specimen usually decreased with higher compaction thickness. The reinforcement increases soil stiffness under the compaction roller and it initiates stress concentration. As a result, it maintains higher vertical stress level on the base of specimen that provides better compaction characteristics. Based on test results, it can be concluded that the reinforcement is essential to achieve effective compaction on soft clay.

• Biomedical Science Letters
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• v.7 no.4
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• pp.181-190
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• 2001

This study was designed to investigate the effects of reactive oxygen species (ROS) on DNA stability in human spermatozoa. To verify human spermatozoa were incubated with xanthine-xanthine oxidase (X 100$\mu$M-XO 50 mlU ~ 400 mIU), $H_2O_2$ (125 $\mu$M ~ 1 mM), sodium nitroprusside (SNP 0.1 $\mu$M ~ 100 $\mu$M) or lymphocyte. Otherwise, spermatozoa were incubated under low $O_2$ (5%) condition. Damage of sperm DNA was analyzed by single cell electrophoresis (Comet assay) and flow cytometry after acridine orange staining. In the presence of ROS, there was increase in DNA damage. The rate of DNA single strand breakage (9.0$\pm$1.0% ~ 46.0$\pm$4.6%) and DNA fragmentation (7.51$\pm$1.0% ~ 29.5$\pm$4.6%) were similar regardless of the kinds of ROS and exposure time. DNA damage in the lower $O_2$ condition (5%) was lower than ambient $O_2$ condition (20%). Taken together, it suggested that sperm DNA might be damaged by ROS. In the presence of ROS, increase in DNA damage and chromatin instability was obvious in spite of short exposure. Although present study reconfirmed that sperm incubation in the low concentration of ROS have the benefit m the induction of capacitation and Ah, the increase in DNA damage by ROS and possible genetic problem should be considered before the human trials.