DEVELOPMETNT OF A NEW SCREENIG SYSTEM FOR WOOD PRSERVATIVES BY USE OF THE INHIBITION FOR WOOD ROTTING FUNGI

本研究的主要目的是在对耐铜木材腐朽菌关键酶抑制剂进行生化分析的基础上，建立一种新的木材防腐剂筛选体系。首先，我们研究了导致铜防腐剂解毒的草酸生物合成的代谢机制，最后，在体外抑制剂筛选系统中，尝试了多种化合物对异柠檬酸裂解酶的抑制作用，获得了以下重要结果，并发表在本文末尾列出的国际期刊上。腐真菌沼泽拟层孔菌（Fomitopsis palustris）与生长在葡萄糖上的正常微生物相比，组成性地包含乙醛酸循环，并且还发现与TCA循环相关的循环与草酸生物合成耦合。2）通过这些与草酸生物合成耦合的代谢循环，异柠檬酸裂解酶（ICL）是木腐菌生长的关键酶之一，在草酸生物合成中起着关键作用; 3）乙醛酸循环的关键酶ICL和苹果酸合成酶（MS）在木腐菌中广泛分布首次从木腐菌中分离纯化了ICL和MS两种关键酶，并与其他来源的酶进行了比较。5）首次在液体培养中成功地制备了沼泽红盖菇子实体。

The primary objective of this research project is to develop a new screening system for wood preservatives on the basis of biochemical analysis of the inhibitors blocking the key enzymes of the copper-tolerant wood rotting fungi. First we investigated metabolic mechanism for biosynthesis of oxalic acid which causes detoxification of copper preservatives, and finally, attempted to test many compounds if they inhibit potently the key enzyme isocitrate lyase in the in vitro inhibitor screening system.The following important findings obtained have been published in the international journals listed at the end of this abstract.1) The brown-rot fungus Fomitopsis palustris contains constitutively the glyoxylate cycle in contrast with the normal microorganisms grown on glucose and the cycle linked with the TCA cycle was also found to couple with the oxalic acid biosynthesis.2) Through these metabolic cycles coupling with the oxalate biosynthesis, the wood-rotting fungi seem to gain the energy for their growth and one of the key enzymes was found to be isocitrate lyase (ICL) which plays a pivotal role for biosynthesis of oxalic acid.3) Both ICL and malate synthase (MS) which are key enzymes of the glyoxylate cycle were found to distribute widely among the both white-rot and brown-rot fungi.4) We have successfully purified these key enzymes (ICL and MS) for the first time from the wood-rotting fungi and characterized for comparison with the enzymes from other sources.5) We also succeeded in making fruit bodies of the F.palustris in the liquid culture for the first time.