• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.263-269
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• 2016

Temperate phages have been suggested to carry virulence factors and other lysogenic conversion genes that play important roles in pathogenicity. In this study, phage TEM123 in wild-type Staphylococcus aureus from food sources was analyzed with respect to its morphology, genome sequence, and antibiotic resistance conversion ability. Phage TEM123 from a mitomycin C-induced lysate of S. aureus was isolated from foods. Morphological analysis under a transmission electron microscope revealed that it belonged to the family Siphoviridae. The genome of phage TEM123 consisted of a double-stranded DNA of 43,786 bp with a G+C content of 34.06%. A bioinformatics analysis of the phage genome identified 43 putative open reading frames (ORFs). ORF1 encoded a protein that was nearly identical to the metallo-β-lactamase enzymes that degrade β-lactam antibiotics. After transduction to S. aureus with phage TEM123, the metallo-β-lactamase gene was confirmed in the transductant by PCR and sequencing analyses. In a β-lactam antibiotic susceptibility test, the transductant was more highly resistant to β-lactam antibiotics than S. aureus S133. Phage TEM123 might play a role in the transfer of β-lactam antibiotic resistance determinants in S. aureus. Therefore, we suggest that the prophage of S. aureus with its exotoxin is a risk factor for food safety in the food chain through lateral gene transfer.

• YAKHAK HOEJI
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• v.49 no.1
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• pp.92-96
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• 2005

In order to investigate the effects of bisphenol A (BPA) on cell mediated immune reaction in vitro we examined the allogenic mixed lymphocyte reaction (MLR), splenocytes proliferation (SP) to T cell mitogens and IFN-${\gamma}\;production$. Splenocytes of Balb/c mice ($1.5{\times}10^5$ cells/well) were co-cultured with different numbers of mitomycin C-treated mature dentritic cells (DCs) in presence of BPA (25, 50, 100 ${\mu}M$) and $[^{3}H]$thymidine incorporation (cpm) was measured by scintilation counting. Splenocytes ($2{\times}10^6$ cells/well) were cultured with mitogens, Con A ($2\;{\mu}g/ml$), PHA ($5\;{\mu}g/ml$) and IL-2 ($0.1\;{\mu}g/ml$), or PMA ($5\;{\mu}g/ml$) and INO ($1\;{\mu}g/ml$) in presence of BPA (1, 10, 25, 50, 100 ${\mu}M$) and SP was assessed by MTT assay. $IFN-{\gamma}$ levels in culture supernant were determined by ELISA. At low concentration, BPA slightly increased MLR, SP and $IFN-{\gamma}$ levels, but at higher concentration it showed significant inhibitory effects on these immunological parameters. These results indicate that BPA is able to alternate cell-mediated immune reaction.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.61-66
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• 2004

70% ethanolic extracts were prepared from the three mutant rice cultivars with giant embryo termed Shinsunchal-giant embryonic rice, Whachung-giant embryonic rice and Nampung-giant embryonic rice, and its antioxidative and antimutagenic properties were evaluated and compared. For analysing antioxidativity, various antioxidative indices, such as electron donating ability to DPPH radical, scavenging capacity to hydroxyl radicals generated by Fenton reaction, scavenging capacity to superoxide radicals generated by HPX/XOD system, inhibitory effect on autoxidation of linoleic acid and inhibitory effect on membrane lipid peroxidation derived from rabbit erythrocyte ghost, were determined. For analysing antimutagenicity, suppressive effects on mutagenesis induced by the chemical mutagen, mitomycin C, were measured using E. coli PQ 37 as a indicator cell. The results showed that for both antioxidativity and antimutagenicity the giant embryonic rices were more effective compared to the general cooking rice, Among the giant embryonic rice cultivars, Nampung-giant embryonic rice tended to be most effective, showing its scavenging activity to DPPH radical, superoxide radical and hydroxyl radical, and inhibitory activity to lipid peroxidation was 2,3-, 3,3-, 1.7-, and 2.5-fold greater than those of normal rice, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.7
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• pp.853-857
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• 2008

To assess the clastogenic effects of the diglyceride preparation containing conjugated linoleic acid (DG+CLA) in vivo micronucleus test was performed using ICR mice. Each of the groups consisted of three doses of DG+CLA (500, 1,000 and 2,000 mg/kg, p.o.), Mitomycin C (positive control, 2 mg/kg, i.p.) and negative control (olive oil, 10 mL/kg, p.o.). A slide preparation was made at 24 hours after 1st treatment with DG+CLA. As a result of counting the icronucleated polychromatic erythrocyte (MNPCE) of 2,000 polychromatic erythrocyte (PCE), the number of aberrant cells was not increased in any of the three doses of DG+CLA orally administered. There was no clinical sign connected with administration of DG+CLA. These results indicate that DG+CLA is not capable of inducing micronuclei in vivo mice cells and thus has no genotoxicity in micronucleus.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.439-445
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• 1998

The antimutagenic activity of the water extract of Rehmannia glutinosa Liboschitz (RG) on the mutagenicity induced by 4-nitroquinoline 1-oxide (4-NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), mitomycin C (MMC), $aflatoxin\;B_1\;(AFB_1)$ and benzo(a)pyrene [B(a)P] were studied using the SOS Chromotest with Escherichia coli PQ37. The water extract of RG was separated into methanol soluble and methanol insoluble parts. The methanol soluble part exhibited higher inhibition effects than the methanol insoluble part against the mutagenic activities of five mutagens. Step-wise fractionation of methanol soluble part was done using methanol, ethyl acetate and water. Among these fractions, water fraction had the strongest inhibitory effects against the mutagenenicity of five model mutagens, showing $4.5{\sim}29.5%$ inhibition, but the $AFB_1$ mutagenic potency was increased slightly by ethyl acetate fraction. The water fraction was further partitioned by sephadex LH-20 column chromtography, and 9 subfractions were obtained. The fraction III showed the strongest inhibitory effects with dose response against the mutagenic activities induced by all the tested chemical mutagens. The inhibition rates of fraction III at concentration of $400\;{\mu}g/assay$ were 29%, 35%, 38%, 25% and 24% against 4-NQO, MNNG, MMC, AFBl and B(a)P, respectively. The fraction III also exhibited a strong bio-an-timutagenicity against 4-NQO and $AFB_1$ by showing more than 40% inhibition.

• Korean Journal of Environmental Agriculture
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• v.33 no.2
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• pp.138-143
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• 2014

BACKGROUND: Azadirachta Indica extract(AIE) and Sophorae radix extract(SRE) are widely used as environment-friendly organic materials of plant origin in South Korea. METHODS AND RESULTS: In this study, the in vitro micronucleus(vitMN) tests of two samples of AIE and SRE were conducted to evaluate their genotoxicity using the Chinese hamster lung(CHL) cell. This study was composed of two parts; cytochalasin B(cyto B) test and non-cyto B test. Mitomycin C and colchicine were used as positive controls. As a result, the incidence of micronucleus(MN) in all AIE and SRE treated groups increased in dose-dependent manner, but were less than 2.2% in 1,000 binucleated cells. In addition, there were no significant increases of MN incidence in all AIE and SRE treated groups, compared with the negative control group. CONCLUSION: Therefore, we suggest that AIE samples and SRE samples used in this study may have no genotoxicity in the in vitro micronucleus test using the CHL cells. In our previous study, we reported that AIE and SRE did not cause genotoxicity in Ames test. According to the genotoxicity battery system, we concluded that AIE and SRE used in this study have no genotoxic effects to humans.

• Korean Journal of Animal Reproduction
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• v.18 no.4
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• pp.235-244
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• 1995

The present study was designed to demonstrate that ES cell lines efficiently could be isolated from explanted blastocysts of hybrid BCF1 mouse when grown on STO feeder layer derived from mouse fibroblasts in culture medium supplemented with leukemia inhibitory factor (LIF). The expanded blastocysts were attached to mitomycin C-inactivated STO feeder layer and were cultured for 4 days. Four days later the ICM was disaggregated by a short term trypsin treatment (0.25% trypsin / 0.04% EDT A for 2-3 min). The resulting cell suspension was seeded on a new STO feeder layer and covered with DMEM supplemented with 10% FCS, 0.1 mM nonessential amino acid, 0.1 mM sodium pyruvate, 0.1 mM mercaptoethanol and 1,000 U/ml LIF. Colonies of ES-like cells were observed after the second passage. These colonies were repeatedly passaged at approximately 5 day intervals. In this study, five ES-like celllines were isolated by directly explanting blastocysts, but three lines were lost after the 5th passage, possibly due to toxic effects of a new FCS batch. The characterization of developmental potential of isolated cell lines was performed with respect to in vitro differentiation and specific activity of alkaline phosphatase (AP). When cells were cultured in suspension, the aggregates of cell lines were capable of forming simple embryoid bodies (EB), and showed the capacity for forming cystic multilayer EBs. In addition, the cell lines were positive for AP staining, a biochemical marker characteristic of mouse ES cells.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.141-147
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• 2000

Interrelation between the antioxidative activity of hot-water extracts of 130 medicinal plants and their cellular antimutagenic activity was investigated. Antioxidative activity was evaluated by assaying electron-donation to DPPH free radical and scavenging of hydroxyl radical $({\cdot}OH)$ generated through Fenton rection, respectively. All medicinal plants examined in this study exhibited markedly electron-donating ability and radical scavenging ability in each assay system. The results demonstrated the fact that Pilbal (Piper longum L.) is the strongest in electron-donating activity, on the other hand, that Seokgok (Dendrobium moniliforme L.) is the strongest in ${\cdot}OH$ scavenging activity. When evaluated their antioxidative activities, 24 medicinal plants including Jimo (Anemarrhena asphodeloides Bunge) were found to be the medicinal plants carrying strong antioxidative activity, which exhibited more than 50% activity compared to the control group in both electron-donating and free radical scavenging. The experiment was also performed to examine whether 11 medicinal plants having significant antimutagenicity damage DNA in the presence of $Cu^{2+}$, showing the fact that all samples tested, except Taeksa (Alisma canaliculatum All. Br.), Paekjain (Nitraria sibirica Pall) and Ohyak (Lindera strychifolia Sieb. et Zucc. Villar) are capable of inducing DNA strand break. We also found that Taeksa and Paekjain strongly block DNA strand break induced by chemical mutagen mitomycin C.

• Applied Biological Chemistry
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• v.47 no.4
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• pp.396-402
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• 2004

For industrial application to manufacturing functional foods for health using browned oak mushroom, we examined its reducing power, inhibitory effect on intracellular reactive oxygen species, phenolic compounds and phytates contents, modulatory effects on NO radical and matrix metalloproteinase 9 (MMP9) generation by activated macrophages, and antimutagenicity in order to evaluate the functionality of browned oak mushroom for health. While overall ethanolic extracts have higher reducing power than aqueous extracts, browning reaction was found to increase reducing power by up to 28% at a 3.32 mg/ml sample concentration. Browning reaction also increased phenolic compound content by about 73% compared to raw mushroom. However, any significant change in phytate content could not be detected. At a concentration of $100\;{\mu}g/ml$, treatment of ethanolic extract of oak mushroom increased NO generation over 43% in LPS-stimulated macrophage. On the contrary, the aqueous extracts rather decreased it over 17% at the same sample dose. However, any solvent extract from browned oak mushroom seems not to cause any change in both NO production and MMP9 activity. In addition, browning reaction did not allow any significant change in suppressive effect on mitomycin C-induced mutagenesis as examined with SOS chromotest. These results suggest a possible use of browned oak mushroom with unmarketable quality as a material for development of a variety of processed functional foods for health.

• Korean Journal of Food Science and Technology
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• v.22 no.6
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• pp.625-631
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• 1990

This study was carried out to investigate the antimutagenic effects of five kinds of apple enzymatic browning reaction products(AEBRP) on mitomycin C (MMC), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitroquinoline-1-oxide(4NQO), benzo(${alpha}$)pyrene(B(${alpha}$)P) and 3-amino-1,4-dimethyl-5H-pyri-do [4,3-b]indol (Trp-P-1). In spore rec-assay using B. subtilis Hl7($rec^+$) and M45($rec^-$), homocatechol-AEBRP and hydroquinone-AEBRP showed strong antimutagenic effects on MMC and MNNG as the concentration of AEBRP increased. In the Ames test using S. typhimurium TA98 and TA100, hydroxyhydroquinone-AEBRP and pyrogallol-AEBRP showed strong antimutagenic effects on Trp-p-1 and B(${alpha}$)p in TA98 and TA100 in the presence of S-9 mix. Most of AEBRPs suppressed about 50% to 80% the mutagenesis in S. typhimurium TA98 induced by MNNG, however, AEBRPs except hydroxyhydroquinone-AEBRP showed antimutagenic effects of about 94% in TA100. Antimutagenic effects of the five kinds of AEBRPs on 4-NQO were more or less weak, in particular homocatechol-AEBRP exhibited the inhibitory effect of about 48% in TA98, and homocatechol-AEBRP and hydroquinone-AEBRP showed inhibitory effects of about 46% to 58% in TA 100.