| Project/Area Number |
10460074
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B).
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
林産学
|
|---|
| Research Institution | KYOTO UNIVERSITY |
|---|
Principal Investigator |
SHIMADA Mikio Kyoto Univ.Wood Res.Institute, Professor, 木質科学研究所, 教授 (50027166)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HATTORI Takefuni Kyoto Univ., Wood.Res.Institute, Instructor, 木質科学研究所, 助手 (60212148)
|
|---|
| Project Period (FY) |
1998 – 2000
|
| Project Status |
Completed (Fiscal Year 2000)
|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,300,000 (Direct Cost: ¥2,300,000)
|
|---|
| Keywords | Wood-rotting fungi / glyoxylate Cycle / Copper-tolerant fungi / TCA cycle / isocitrate lyase / malate synthase / Tyromyces palustris / oxalate biosynthesis / シュウ酸生合成 / シュウ酸 / きのこ / 酵素 / 褐色腐朽菌 / グリオキシレート脱水素酵素 / 阻害剤 / グリオキシル酸 |
|---|
| Research Abstract |
Copper-tolerant wood rotting fungi most of which belong to a group of brown-rot basidiomycestes have been recognized to detoxicate copper-contining wood preservertives by precipitating copper into copper oxalate by biosynthesis of oxlate. Thus, it is very important to elucidate biochemical mechanisms for oxalate biosyntheis in these copper-tolerant fungi.
New findings obtained by this ivestigation are summized as follows.
1. We have discovered that most of the wood-rotting basidiomyceses have the glyoxylate cycle enzymes although thy were grown on gluose-rich medium, which is sharply contrasted with the clasical view that the glyolxylate cycle enzymes are repressed in microorganisms grown on glucose.
2. We sucessfuly purified and characterized the key enzymes of the glyxolylate cycle such as isocitrate lyase (ICL) and malate synthase (MS) for the first time from a basidiomycetous fungus Tyromyces (Fomitopsis) palustris, which is a copper-tolerant fungus.
3. Importanlty, we could successful
… More
ly control the copper-tolerant fungus Tyromyces palustris with ICL enzyme inhibior, which also found potently inhibit the oxalate bioxynthesis. We have found that both TCA and glyoxylate cycles play an important role in biosynthesis of oxalic acid to produce energy for the fungal growth
4. During the fruitbody formation of the brown-rot fungus, the oxalate biosynthesis was ceased and the glyoxylate cycle enzymes and oxalate producing enzynes disappeared, whereas isocitate dehydrogenase (ICDH) was activated and predominate over the ICL.The results further indicate that at the later stage of thefungal growth ICDH played more important role than ICL to support the GABA route for operation of the TCA cycle.
5. Importantly, throughout the life cycle of thisfungus, it was found to lack a-ketoglutarate decarbxylase which is a key enzyme of normal TCA cycle functioning in both plants and animals. Thus, the glyoxylate cycle and GABA route play alternately importantl role to compensate the desfunction of the normal TCA cycle in these copper-tolerant fungi. Less
|
