The involvement of extracellular substances for the generation of hydroxyl radical during wood degradation by white-rot fungi

在目前的研究中，我们研究了一个电子氧化活动的可能作用，由苯酚氧化物和羟基化合物在木材退化中产生的提取物低分子重量物质，我们演示的羟基基化合物在四个白色基化合物期间产生的木材退化。木材的退化率与P. Chrysosporium相关，与羟基生成良好，与低分子重量的片段相比，乙烯生成良好。同样的趋势也是在C. versicolor上看到的。对苯醇氧化酶活性的研究表明，P.在木材文化中主要生产的锰过氧化物酶和在孵化早期阶段生产的锰过氧化物酶和过氧化物酶。C. Versicolor主要在木材文化中生产过氧化物酶和乳酸，并保留了几乎相同的活动水平。因此，该物质的基础特性和苯醇氧化酶的常量从另一个方面有很大不同。从某种意义上说，木质上白团真菌的退化率并不依赖于氧化物的活性物如phenol oxidases. Immunogold-TEM使用多克隆抗体来提高针对Tyromyces palustris extracellular低分子重量物质的差异演示了在细胞内的真菌超声波发光到S_2细胞壁。羟基分子攻击木材成分，并由于退化的初始步骤，它是通过分离的共同边界来破坏刚性结构的。进一步的， HO·可能实现其他结构性变化，使其Facilitate the subsequent enzymatic breakdown of the fragments被oxidative enzymes秘密降解，由white-rot fungi负责。白腐真菌生产氧化酶，能够完成对木材的破坏。

In the present research, we examined the possible roles of one-electron oxidation activity by phenol oxidases and hydroxyl radicals produced by extracellular low molecular weight substances in wood degradation by white-rot fungi.We demonstrated hydroxyl radical was produced during wood degradation by four white-rot fungi. The rate of degradation of wood by P.chrysosporium correlated with hydroxyl radical generation as well as ethylene generation by fractions of low molecular weight. The same tendency was observed in C.versicolor. The assay for phenol oxidase activity proved that P.chrysosporium produced manganese peroxidase dominantly in wood cultures and produced manganese peroxidase and peroxidase in the very early stage of incubation. C.versicolor produced mainly peroxidase and laccase in wood cultures and retained almost same level of activity throughout incubation. Therefore, the substrate specificity and the constituent of phenol oxidizing enzymes of the fungus were very different from another. Consequently, the rate of degradation of wood by white-rot fungi was not dependent upon the activities of oxidants such as phenol oxidases.Immunogold-TEM using polyclonal antibodies raised against Tyromyces palustris extracellular low molecular weight substance demonstrated the diffusion of the substance from the fungal hyphae within the cell lumen to the S_2 cell wall.In conclusion, hydroxyl radicals attack the wood component and cause the initial step of degradation, which is destruction of the rigid structure by cleavage of covalent bonds. Further, HO・may achieve other structural changes to facilitate the subsequent enzymatic breakdown of the fragments which were degraded by oxidative enzymes secreted by white-rot fungi. White-rot fungi produce oxidative enzymes, capable of completing the breakdown of wood.