• 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.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권6호
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• pp.400-406
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• 2000

Since the 1950s, the numbers of species and chemicals produced have significantly increased. Despite the fact that industrial chemicals have given us numerous benefits, there is no doubt that they have damaged the environment. The chemicals being dispersed on the earth should be carefully controlled to prevent adverse effects. Bioassay is one of the methods to assess chemical safety. In bioassay systems, chemical safety is estimated by monitoring biological responses to environmental pollutants and newly synthesized chemicals. This report introduces multiple-point bioassay systems that are based on chemical sensitivities of microorganisms, responses of one kind of organism, and micro-array technology. Multiple-end-point bioassays enable the prediction of chemicals in the environment and the understanding of toxicities of newly synthesized chemicals.

• Journal of Ginseng Research
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• 제5권1호
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• pp.24-34
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• 1981

For bioassay of the various extracts of ginseng, the growth determination method using Saccharomyces cerevisiae which was cultured with various doses of the extracts, was studied The water extract, Powder. and ethanol extract were more effective (about 45∼ 110% increase) than saponins or its fractions (about 20∼35% increase). The cold methanol residue showed a increase effect but it was not significant. The bioassay curves for the water extract, ethanol extract, the butanol extracted saponins and the cold methanol- residue were made from the experimental data. From these curves it is possible to find the relation between dose and effectiveness and the optimal doses of various ginseng extracts, and the amount of extract in a sample can be estimated The .angers of sample amount were 0.01% (100ppm) ∼0.32% (3200ppm) fo. the water extract, 0.025% (150ppm)∼0.1% (1000ppm) for the ethanol extract, and 0.008% (80ppm)∼0.016% (160ppm) for the saponins. It was impossible to determine the range for the cold methanol- residue, The acceleration effects on the cell proliferation by a only 0.0008% (8ppm) of the diol- and triol-saponin were measurable in earlier Period (24 hour treatment).

• 한국미생물·생명공학회지
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• 제19권6호
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• pp.588-591
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• 1991

S-adenosyl-L-methionine(SAM)은 생체 메칠화 반응에 긴요한 기질이다. 이 논문은 효모 발효에 의한 SAM의 실험실 규모 생산의 최적조건을 다시 검토한 것이다. 발효 배지는 메치오닌을 첨가했으며 배양조건들을 재조절하였다. 분리과정은 추출, 앙금 및 크로마토그래피를 포함한 다섯단계로 이루어졌다. 이 향상된 과정은 원래 방법보다 비교적 높은 생산 수득률로 생활성 있는 SAM을 4일 이내에 제공해준다.

• Journal of the Korean Wood Science and Technology
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• 제29권3호
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• pp.92-98
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• 2001

Allelopathic effects of the cork tree (Phellodendron amurense Rupr.) on several crops and soil miro-organisms were assessed using germination bioassay and antimicrobial assay, and allelochemicals were identified. In a germination bioassay, extract of cork tree inhibited at high concentration on germination of several crop seeds such as cabbage, lettuce, and cucumber. However, aqueous extracts inhibited powerfully growth of test organisms such as Streptococus aureus, S. aureus, S. typhimurium, and E. coli as bacteria, and Candida albicans as yeast, and Botrytis cineria and Alternata alternaria as fungi.. The cork tree extract showed strong antimicrobial activities against isolated soil fungi. The allelochemicals were separated using Silica gel, Sephadex LH-20 gel column chromatography and HPLC. The substances were analyzed by UV spectrometry and EI-mass spectrometry. The active allelochemicals were identified as isoquinoline alkaloids, berberine and palmatine.

• 한국물환경학회지
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• 제20권1호
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• pp.48-54
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• 2004

Two methods, a Ceriodaphnia algal uptake suppression test (CAUST) and a new toxicity test based on temperature control (TTBTC) which are based on feeding behaviour and temperature control, respectively, were developed and compared for the adoption as the better methodology for short-term toxicity screening. As previously published by Lee et aI., (1997), the CAUST method is based on the feeding behaviour of C. dubia and requires as little as 1 hour of contact time between C. dubia neonates and toxicant. However, even though CAUST requires only 1 hour of contact time, this method still take many hours for the preparation and measurement. Before the test starts, neonate digestive tracts were cleared by feeding yeast to the daphnids, Neonates were then exposed to toxicant, followed by addition of Scenedesmus subspiatus into the bioassay vessels. Daphnids were examined under the bright-field microscope with the presence of algae (indicated by a green colored digestive tract) or the absence of algae. Uptake indicated no toxic effect, whereas, absence of uptake indicated toxic inhibition. Unlike CAUST, the newly developed method (TTBTC) is based on just temperature control for the toxicity test of C. dubia. Initially, neonates are exposed to toxicants while the temperature of water bath containing media increased to $35.5^{\circ}C$. After 1.25 hour of contact time, the number of the daphnids, either live (no toxic effect) or dead (toxic effect), is counted without the aid of any instrument. In both methods, median effective concentrations ($EC_{50}$ values) were computed based on the results over a range of dosed toxicant concentrations. It showed that TTBTC was as sensitive as the standard 48-hour acute bioassay and CAUST. TTBTC and CAUST were much more sensitive than the I-hour I.Q. test and 30-minute Microtox. This study indicates that TTBTC is an easier and more rapid toxicity test than the standard 48-hour acute bioassay and even CAUST.

• 한국환경농학회지
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• 제27권4호
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• pp.447-455
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• 2008

Recombinant yeast estrogenicity (YES) assay was used as a bioanalytical tool in order to screen $17{\beta}$-estradiol in the soil samples collected from different sites of South Korea. Solvent extraction and supercritical fluid extraction (SFE) methods were compared for the extraction of the estradiol from the soils. Most high detection of the estradiol based on YES assay was observed in the soils extracted with methanol. Different types of estrogenic hormones including $17{\beta}$-estradiol were suggested to be possibly exiting in the soils, since the methanol extracts of the soils showed an estrogenic activity that was not observed in the hexane extracts of the soil. SFE extracts showed estrogenic activity in some of the samples but methanol extract showed best activity.

• 생명과학회지
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• 제16권6호
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• pp.919-924
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• 2006

다양한 독성물질 및 이들의 대사산물의 효율적인 생물독성 평가시스템이 지속적으로 개발되고 있다. 본 연구에서는 대분비계 교란물질인 endosulfan, bisphenol A, vinclozolin 및 3,5-dichloroaniline을 대상으로 인간 간암세포주, 지렁이, 효모를 이용한 세포독성 및 성장억제 효과를 평가하였다. 인간 간암세포주 독성평가에서는 endosulfan, 3,5-dichloroaniline, bisphenol A의 순으로 독성이 나타났으며, 지렁이 독성평가에서는 endosulfan, bisphenol A, 3,5-dichloroaniline의 순으로 독성이 나타났다. 효모를 이용한 독성평가에서는 3,5-dichloroaniline, endosulfan, bisphenol A의 순으로 독성이 나타나 다른 시스템과는 부분적인 차이가 나타났으며, vinclozolin의 경우 3가지 독성평가 시스템에서 모두 독성이 나타나지 않았다. 이러한 결과는, 동일한 물질을 서로 다른 생물 독성평가 시스템을 사용하여 평가하는 경우, 부분적인 오류가 나타날 수 있음을 암시하고 있으며, 독성 유무 판단은 가능하더라도, 독성 정량평가 및 독성 정도를 비교하는 것은 어렵다는 것을 제시하고 있다. 또한 본 결과는, 다양한 물질 및 이들의 대사산물의 일차적 독성평가에는 지렁이 및 효모시스템이 빠르고 경제적임을 암시하고 있으며, 독성이 인정될 경우 인간세포주 및 동물시험에 의한 검증이 효율적이라고 판단된다.

• 한국응용곤충학회지
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• 제53권1호
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• pp.27-34
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• 2014

자연 감염된 담배가루이로부터 곤충병원성진균을 분리 동정하고, 이 균주에 대하여 배양특성, 자연발병 요인, 그리고 주요 온실해충인 담배가루이, 점박이응애, 대만총채벌레에 대한 살충력을 검정하였다. 분리 균주의 형태적 특성은 직립한 분생자병에 윤생으로 호리병 형태의 4-6개 phialide를 지녔고, 분생포자의 크기는 $3.0-3.4{\mu}m$ 이었다. 분리 균주의 rDNA의 ITS영역 염기서열 분석에서 Isaria fumosorosea (AF461747)와는 99%의 높은 염기서열 유사도를 보였다. Potato dextrose agar, Sabouraud maltose agar+yeast extract 그리고 Sabouraud dextrose agar+yeast extract 배지에서 IFs 균주는 $24^{\circ}C$의 SDAY 배양에서 균사 성장이 가장 양호하였으며, $15^{\circ}C$보다는 $35^{\circ}C$의 고온에서 균사 성장이 좋았다. I. fumosorosea IFs-08, -09 균주는 담배가루이에 대하여 각각 96.7, 93.9%의 높은 살충율을 보였으며, 점박이응애(92.0, 84.9%) 그리고 대만총채벌레(84.4, 81.5%)에서도 80-90%정도의 살충율을 보인 반면 KACC로부터 분양받은 Isaria tenuipes, Isaria farinosa, Isaria fumosorosea 균주들은 10-20% 내외의 낮은 살충율을 나타내었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권4호
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• pp.292-296
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• 2004

The recombinant soluble human tumor necrosis factor-alpha (hTNF-$\alpha$) was expressed in a yeast Saccharomyces cerevisiae and its cytotoxicity was evaluated. A cDNA encoding hTNF-$\alpha$ was placed under the control of two different promoters: a glyceraldehyde-3-phosphate dehydrogenase (GPD) promoter and a yeast hybrid ADH2-GPD promoter, consisting of alcohol dehydrogenase II (ADH2) and the GPD promoter. A Northern blot analysis revealed that, although variation in the expression level of hTNF-$\alpha$ existed among transformants, the higher expression was obtained with the GPD promoter. Expressed hTNF-$\alpha$ protein (rhTNF-$\alpha$) was successfully secreted into the culture medium, producing 2.5 mg per liter of culture filtrate, with no changes in cell growth. The bioassay for observing the cytotoxicity to the murine L929 fibroblast cell line, with serial dilution of rhTNF-$\alpha$, indicated that the secreted rhTNF-$\alpha$ was bioactive and its dose-response was improved eight to ten times over that of the E. coli-derived rhTNF-$\alpha$.