| Co-Investigator(Kenkyū-buntansha) |
NOJIRI Hideaki Biotechnology Research Center, The University of Tokyo, Associate Professor, 生物生産工学研究センター, 助教授 (90272468)
NISHIYAMA Makoto Biotechnology Research Center, The University of Tokyo, Associate Professor, 生物生産工学研究センター, 助教授 (00208240)
YAMANE Hisakazu Biotechnology Research Center, The University of Tokyo, Professor, 生物生産工学研究センター, 教授 (80090520)
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| Research Abstract |
[1] Two kinds of bacteria, a dinenzofuran (DF)-degrader Terrabacter sp. strain DBF63 and a carbazole (CAR)-degrader Pseudomonas resinovorans strain CA10, were investigated for their ability to transform several chlorinated DFs and dibenzo-p-dioxins (DDs). It was shown that CAR 1,9a-dioxygenase from strain CA10 catalyzed angular dioxygenation of all mono- to tri-chioro-DF/DDs (CDF/CDDs) investigated in this study, but DF 4,4a-dioxygenase from strain DBF63 did not transform 2,7-diCDD. We also tried a preliminary bioremediation of the actual dioxin-contaminated soil using the soil-slurry system. The decrease of total CDD and CDF congeners by single inoculation with CA10 or DBF63 cells were 8.3 and 10%, respectively, after 7-day incubation, thus it was shown that strains CA10 and DBF63 had a potential to degrade tetra- to hepta-chlorinated congeners including the most toxic compound, 2,3,7,8-tetraCDD.
[2] The fluorogenic probe assay, competitive PCR and co-extraction with internal standard cells were combined to develop a rapid, sensitive, and accurate quantification method for the copy number of a target carAa gene and the cell number of strain CA10. In addition, by using Tn5 transposon, strain CA10 was chromosomally marked with a tandem gfp gene. The real-time competitive PCR and direct counting using the GFP marker were employed to monitor the total number of carAa gene and survival of strain CA10 cells in the soil.
[3] Following plate matings between CAR-degrader strain K23 and phenol-degrader strain DS1 in the presence of CAR, transconjugants able to utilize CAR were obtained. The transconjugants had large plasmid pCAR2.
[4] Transgenic plants expressing DbfB fused to endoplasmic reticulum signal peptide continuously secrete recombinant proteins from their roots into a simple hydroponic medium, and the secreted DbfB proteins retained biological activity.
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