• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.223.1-223
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• 2005

• Toxicological Research
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• 제17권1호
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• pp.65-71
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• 2001

The key targets of endocrine disruptors are nuclear hormone receptors, which bind to steroid hormones and regulate their gene transcription. A yeast-based steroid hormone receptor gene trascription assay was previously developed for the evaluation of chemicals with endocrine modulating activity. The yeast transformants used in this assay contain the human estrogen receptor along with the appropriate steroid response elements upstream of the $\beta$-galactosidase reporter gene. We tried to evaluate several natural and synthetic steroids of their potential to interact directly with the steroid receptor. Some putative endocrine disruptors, including nonylphenol, are weakly estrogenic. But the combined treatment oj these chemicals with di-(2-ethylhexyl)phthalate (DEHP) significantly increased the $\beta$-galactosidase activity in the yeast transformant. These results suggest that we also have to consider the synergistic effects of endocrine disruptors. In this study, we showed that yeast-based bioassay is a valuable tool for screening potential endocrine disruptors and quantitative determination of estrogenicity. And the possibility that the estrogen receptor binds multiple environmental chemicals adds another level of complexity to the interaction between the endocrine disruptors and the human hormone system.

• Journal of Microbiology
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• 제45권6호
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• pp.583-589
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• 2007

The promoter region of pyrC (dihydroorotase) gene of Escherichia coli was shown to have Fur protein binding properties by gel retardation assay. In vivo regulation of the pyrC expression was studied by measuring dihydroorotase activity and ${\beta}$-galactosidase level in the $fur^+$ and $fur^-$ genetic background. The expression of chromosomal dihydroorotase activity and ${\beta}$-galactosidase activity of pyrC-lacZ fusion plasmid was repressed to about 30% and 17%, respectively in the $fur^+$ strain compared to those in the $fur^-$ strain. Divalent ions such as $Fe^{2+}$ and $Zn^{2+}$ were not required for the repression. PyrC expression was also reduced to one half by 1 mM uracil. The effect of uracil was independent on the fur gene.

• Journal of Animal Science and Technology
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• 제45권2호
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• pp.211-218
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• 2003

본 연구는 양돈사료내 대두박 항영양인자인 $\alpha$-galactosides와 galatomannan의 분해를 유도하는 $\alpha$-1,6-galactosidase와 $\beta$-1,4-mannanase의 사료내 첨가가 자돈 및 육성돈의 성장과 영양소 소화율에 미치는 영향을 조사하기 위하여 실시하였다. 시험 1은 개시시 체중 10.57$\pm$0.30kg의 3원 교잡종 자돈 60두를 공시하였으며, 시험설계는 옥수수－건조유청－대두박 위주의 사료에 NRC (1998)의 영양소 요구량에 따라 처리한 대조구 (CON), 대조구 사료내 복합효소제를 0.1% 첨가한 처리구로 하였다. 사양시험기간동안, 일당증체량에 있어서는 대조구와 비교하여 EC0.1 처리구가 높은 것으로 평가되었으나 유의적인 차이는 보이지 않았다. 그러나 사료효율에 있어서는 대조구와 비교하여 EC0.1 처리구가 유의적으로 높게 평가되었다 (P<0.05). 건물과 질소 소화율에 있어서 대조구와 비교하여 처리구가 향상된 것으로 조사되었다 (P<0.05). 시험 2는 개시시 체중 22.30$\pm$0.45kg의 3원 교잡종 육성돈 36두를 공시하였으며, 시험설계는 옥수수－대두박 위주의 사료에 NRC (1998)의 영양소 요구량에 따라 처리한 대조구 (AME, adequate ME diet), 대조구 사료내 복합효소제를 0.1% 첨가한 처리구 (AME+EC0.1, Adequate ME diet+ 0.1% 복합효소제), 대조구 사료에서 대사에너지 함량을 4% 낮춘 사료에 복합효소제를 0.1% 첨가한 처리구 (LME+EC0.1, Low ME diet + 0.1% 복합효소제)로 하였다. 총 30일간의 사양시험 기간동안, 일당증체량에 있어서는 AME 처리구와 비교하여 복합효소제 처리구가 유의적인 성장율이 높은 것으로 조사되었다 (P<0.05). 건물 및 질소 소화율에 있어서는 AME 처리구와 비교하여 복합효소제 첨가구가 유의적으로 높게 평가되었다 (P<0.05). 결론적으로, 자돈 및 육성돈 사료에 복합효소제의 첨가는 성장능력 및 영양소 소화율을 향상시키는 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.293-299
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• 2000

Many methods have been developed for screening chemicals with hormonal activity. Using recombinant yeasts expressing either human estrogen receptor [Saccharomyces cerevisiae ER + LYS 8127 (YER)] or androgen receptor [S. cerevisiae AR + 8320 (YAR)], we evaluated the hormonal activities of several chemicals by induction of ${\beta}-galactosidase$ activity. The chemicals were $17{\beta}-estradiol$ (E2), testosterone (T), ${\rho}-nonylphenol$ (NP), bisphenol A (BPA), genistein (GEN), 2-bromopropane (2-BP), dibutyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and butylparaben (BP). To assess the estrogenicity of NP, the result of the in vitro recombinant yeast assay was compared with an E-screen assay using MCF-7 human breast cancer cells and an uterotrophid assay using ovariectomized mice. In the YER yeast cells, E2, NP, BPA, GEN, and BP exhibited estrogenicity in a doseresponse manner, while TCDD did not. All the chemicals tested, except T, did not show androgenicity in the YAR yeast cell. The sensitivity of the yeast (YER) assay system to the estrogenic effect of NP was similar to that of the E-screen assay. NP was also estrogenic in the uterotrophic assay. However, in terms of convenience and costs, the yeast assay was superior to the E-screen assay or uterotrophic assay. These results suggest that the recombinant yeast assay can be used as a rapid tool for detecting chemicals with hormonal activities.

• 대한화장품학회지
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• 제44권3호
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• pp.343-347
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• 2018

화장품에 방부제(살균/보존제)로 사용되는 1, 2-hexanediol (HD)로 인한 부작용을 극복하기 위하여, Escherichia coli (E. coli)의 ${\beta}-galactosidase$ (${\beta}-gal$)를 이용하여 transgalactosylation 반응으로 1, 2-hexanediol galactoside (HD-Gal)를 합성하였다. 본 연구에서는 합성된 HD-Gal의 인간 피부세포에 대한 독성이 어느 정도인지를 HD와 비교하여 관찰하였다. HD-Gal과 HD의 세포독성은 인간 피부각질형성세포(HaCaT cell line)에 HD와 HD-Gal을 처리한 후, cell proliferation assay를 이용하여 비교 분석하였다. 또한 이때, 위상차 현미경으로 HD-Gal과 HD로 처리한 세포의 상태를 비교 관찰하였다. 그 결과, HD-Gal은 42.2 mM에서 211 mM의 농도 범위에서 세포독성이 관찰되지 않았으며, 현미경 관찰에서도 큰 변화를 관찰할 수 없었다. 그러나, HD의 경우에는 저농도에서(42.2 mM and 84.4 mM)는 세포독성이 관찰되지 않았으나, 고농도(168.8 and 211 mM)에서 매우 높은 세포독성을 나타내었고, 현미경 관찰에서는 고농도에서는 물론이고, 세포독성이 관찰되지 않은 HD의 저농도에서도 세포모양과 세포 수에서의 변화가 관찰되었다. 앞으로 세포독성이 감소된 HD-Gal이 HD의 대체제로서 안전, 건강 및 웰빙 개념의 새로운 용도로 개발될 수 있을 것으로 생각된다.

• 한국식품저장유통학회지
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• 제15권5호
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• pp.617-621
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• 2008

Sequential passes through $Sephadex^{TM}$ columns were used to select phages that displays ligands for dextran ($\alpha$-1,6 linked linear chains) from a phage antibody library. Those phages that bound to the $Sephadex^{TM}$ in each iteration were replicated in E. coli. A phage preparation isolated on the third round selection produced 5.4 nephelos turbidity units (NTU) in a dextran specific immunonephelometric assay, a 2.2 fold higher value than the phage preparation from the first round selection. This phage gave $72\;{\pm}\;10$ normalized intensity (N.I.) in a dip-stick assay against high molecular size dextran (T2000, $2\;{\times}\;10^6) and significantly lower color ($30\;{\pm}\;6$ N.I.) against low molecular size dextran (T10, $10^4$). The presence of an Fab insert in each of these phages was confirmed using a $\beta-galactosidase linked assay and polymerase chain reaction.

• 한국식품과학회지
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• 제37권4호
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• pp.549-556
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• 2005

45종 식용 및 약용식물 에탄을 추출물의 에스트로젠 활성 및 항산화활성을 측정하였고 폴리페놀과 플라보노이드 함량을 측정 비교하였다. 재조합 효모법을 이용하여 에스트로젠 활성을 측정한 결과 감초, 강황, 경포부자, 구아바, 느릅(줄기), 도꾸다미, 백화사설초, 대황, 상백피(중국산), 상황버섯, 석류, 복분자(과육, 씨), 원지, 은행, 초두구, 홍화, 황정이 유의적으로 높은 활성을 나타내었다. 특히, 감초와, 대황은 $100{\mu}g/mL$의 농도에서 1mg/mL 보다 더 높은 활성을 나타내었다. DPPH 라디칼 소거능과 TBARS 생성 억제능 두 가지가 모두 우수한 소재는 감초, 구아바, 느릅, 대황, 복분자, 초두구였다. 총 폴리페놀은 초두구가 594.7mg/g catechin eq.으로 가장 높았으며 삼칠근이 8.6mg/g catechin eq.으로 가장 낮았고, 플라보노이드 함량은 강황이 약 394.9mg/g naringin eq.으로 가장 높았고 황정이 1.7mg/g naringin eq.으로 가장 적었다. 폴리페놀의 함량이 높은 식물의 대부분이 플라보노이드의 함량도 많았다. 시료 추출물의 라디칼 소거 활성과 폴리페놀 함량간에 양의 상관관계를 나타내었으나$(r^2=0.61)$, 지질 과산화 억제능 및 에스트로젠 활성과 폴리페놀 함량 간에는 유의적인 상관성이 적었다. 감초, 대황은 에스트로젠 활성이 높으면서 항산화능이 높았다. 이상의 결과는 파이토에스트로젠 활성을 가진 천연 소재를 선정하는데 기초 자료로 활용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제11권3호
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• pp.524-528
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• 2001

The measurement of radiation response using simple and informative techniques would be of great value in studying the genetic risk following occupational, therapeutic, or accidental exposure to radiation. When patients receive radiation therapy, many suffer from side effects. Since each patient receives a different dose due to different physical conditions, it is important to measure the exact dose of radiation received by each patient to lessen the side effects. Even though several biological dosimetric systems have already been developed, there is no ideal system that can satisfy all the criteria for an idean dosimetric system, especially for low-dose radiation as used in radiation therapy. In this study, an SOS Chromotest of E. coli PQ37 was evaluated as a novel dosimeter for low-dose gamma-rays. E. coli PQ37 was originally developed to screen chemical mutagens using the SOS Chromotest-a colorimtric assay, based on the induction of ${\beta}$-galactosidase ue to DNA damage. The survival fraction of E. coli PQ37 decreased dose-dependently with an increasing dose of cobalt-60 gamma-rays. Also, a good linear correlation was found between the biological damage revealed by the ${\beta}$-galactosidase expression and the doses of gamma-rays. The expression of ${\beta}$-galactosidase activity that responded to low-dose radiation under 1 Gy was $Y=0.404+(0.089{\pm}0.3)D+(-0.018{\pm}0.16)D^2$ (Y, absorbance at 420 nm; D, Dose of irradiation) as calculated using Graph Pad In Plot and Excel. When a rabbit was fed with capsules containing an agar block embdded with E. coli PQ37 showed a linear response to the radiation doses. Accordingly, the results confirm that E. coli PQ37 can be used as a sensitive biological dosimeter fro cobalt-60 gamma-rays. To the best of our knowledge, this is the first time that a bacterium has been used as a biological dosimeter, especially for low-dose radiation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권4호
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• pp.322-328
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• 2005

Acylhomoserine lactones (AHLs) are known to be the triggering molecules in the quorum sensing mechanism of many gram-negative bacteria. In order to detect AHL inhibitors that are potential biofilm inhibitors, a convenient and sensitive bioassay was developed based on the $\beta$-galactosidase activity ($\beta$-GAL) of a recombinant Agrobacterium tumefaciens strain. A series of commercially available AHLs were tested for inducing $\beta$-GAL at varying concentrations in agar-plate and liquid cultures of the reporter strain. All AHLs tested exhibited a concentration­dependent induction, and octanoyl homoserine lactone (OHL) showed the highest sensitivity with a detection limit of 0.1 nM in the liquid culture assay. When fimbrolide, a known quorum sensing inhibitor, was added, induction of $\beta$-GAL by OHL was repressed. The repression at a constant OHL concentration was dependent on the fimbrolide concentration with the detection limit below 1 ppm, indicating that this assay is a sensitive method for screening AHL inhibitors.