• 한국환경농학회지
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• 제4권2호
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• pp.95-101
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• 1985

1982년 11월부터 1983년 10월까지 서호를 포함한 수인근교의 저수지 및 한강의 하천수질 시료를 수집, PCBs 및 유기염소계살충제 잔류수준을 평가한 결과는 다음과 같다. 1) PCBs는 거의 모든 수질시료에서 검출되었다. 2) PCBs의 펑균잔류수준은 0.009${\sim}$0.5ppb였고 유기 염소계 살충제의 평균잔류수준은 불검출${\sim}$0.008ppb 였다. 3) PCBs와 총 DDT의 평균잔류수준비는 시료채취 지점에 따라 차이가 있었으며, 이 비는 한강수질시료에서는 500으로 가장 높았고, 원천 수질에서 가장 낮았다. 4) 관개수중 PCBs는 공업 및 도시폐수에서 유래된 것으로 보였다.

• Journal of Microbiology and Biotechnology
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• 제11권6호
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• pp.915-921
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• 2001

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals, and reduces the phosphorus pollution of animal waste. In order to express a high level of fungal phytase in Saccharomyces cerevisiae, various expression vectors were constructed with different combinations of promoters, translation enhancers, signal peptides, and terminator. Three different promoters fused to the phytase gene (phyA) from Aspergillus niger were tested: a galactokinase (GAL1) promoter, glyceraldehyde-3-phosphate dehydrogenase (GPD) promoter, and yeast hybrid ADH2-GPD promoter consisting of alcohol dehydrogenase II (ADH2) and a GPD promoter. The signal peptides of phytase, glucose oxidase (GO), and rice amylase 1A(RAmy1A) were included. Plus, the translation enhancers of the ${\Omega}$ sequence and UTR70 from the tobacco mosaic virus (TMV) and spinach, respectively, were also tested. Among the recombinant vectors, pGphyA06 containing the GPD promoter, the ${\Omega}$ sequence, RAmy1A, and GAL7 terminator expressed the highest phytase activity in a culture filtrate, which was estimated at 20 IU/ml. An intracellular localization of the expressed phytase activity in a culture filtrate, which was estimated at 20 IU/ml. An intracellular localization of the expressed phytase was also performed by inserting an endoplasmic reticulum (ER) retention signal, KDEL sequence, into the C-terminus of the phytase within the vector pHphyA-6. It appeared that the KDEL sequence directed most of the early expression of phytase into the intracellular compartment yet more than $60\%$ of the total phytase activity was still retained within the cell even after the prolonged (>3 days) incubation of the transformant. However, the intracellular enzyme activity of the transformant without a KDEL sequence was as high as that of the extracellular one, thereby strongly suggesting that the secretion of phytase in S. cerevisiae appeared to be the rate-limiting step for the expression of a large amount of extracellular recombinant phytase, when compared with other yeasts.