| Project/Area Number |
12480152
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
環境影響評価(含放射線生物学)
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
YAMAMOTO Kazuo Graduate School of Life Science, Professor, 大学院・生命科学研究科, 教授 (20093536)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
鳴海 一成 日本原子力研究所, イオンビーム生物応用研究部・バイオ技術研究室, 副主任研究員
ISSAY Narumi Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, Principal Investigator
|
|---|
| Project Period (FY) |
2000 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
|
| Budget Amount *help |
¥14,700,000 (Direct Cost: ¥14,700,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2001: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2000: ¥9,900,000 (Direct Cost: ¥9,900,000)
|
|---|
| Keywords | Deinococcus radiodurans / double strand DNA break / DNA damage repair / adaptation / radiation resistance / genome structure / 5-fluorouracil-resistant / genome instability / D. radiodurans / ゲノム安定性 / ゲノムDNA解読 / recA遺伝子 / 自然突然変異 / リファンピシン抵抗性 / D radiodurans / 紫外線耐性 / UVDE遺伝子 / uvrA遺伝子 / 誘発突然差異 / 損傷除去 / D.radiodurans / recA遺伝子homolog / 全ゲノム配列 / dnaA遺伝子 / erroe-free |
|---|
| Research Abstract |
Deinococcus radiodurans is a Gram-positive, red-pigmented, nonmotile bacterium that was originally identified as a contaminant of irradiated canned meat at 1957. It has been isolated worldwide from locations rich in organic nutrients such as animal feces and processed meat. D.radiodurans is an extremely resistant to a number of agents and conditions that damage DNA, including ionizing and ultraviolet radiation and hydrogen peroxide. When an exponential-phase culture of D. radiodurans is exposed to 6000 Gy x-rays, more than 200 double-strand breads (DSB) are introduced into the chromosome. The DSBs are not only repaired without loss of viability, but the chromosome is also apparently resembled so that the linear continuity of the genomes is unaffected by either the damage or the repair process. The capacity of D. radioudurans to survive.
DNA damage suggests that 1)they have the ability to potentiate the effectiveness of the conventional complement of DNA repair proteins, or that 2)they employ repair mechanisms that are fundamentally different from other prokaryotes. Our results indicate that 1)there are at least four identical copies of chromosome per cell, 2)they have not only Escherichia coli homologs for DNA repair, such as the recA, lexA and uvrA, but also several of DNA repair genes which have not been identified, 3)they can restore DNA structure from 200 or more DSBs within 4 hours, and for the processes, recA and unknown genes are involved, and that 4)recA deficient strains have a mutator phenotype if 5-fluorouracil-resistant mutation is monitored, suggesting the role of genome instability.
|
