Reactive oxygen species as agents of wood decay by fungi
Reactive oxygen species as agents of wood decay by fungi
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DOI：
10.1016/s0141-0229(02)00011-x
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发表时间：
2002-04-16
影响因子：
3.4
通讯作者：
Ryan, ZC
中科院分区：
文献类型：
--
作者：
Hammel, KE;Kapich, AN;Ryan, ZC
尽管许多木材腐朽菌分泌氧化和水解酶参与木质纤维素的生物降解，但现在普遍认识到这些酶不能穿透完好的木材，真菌必须使用较小的试剂来引发腐朽。活性氧（ROS）是可能的候选者。越来越多的证据表明，一些木材腐烂真菌产生这些氧化剂。例如，我们观察到。当它们生长在木材上时，白色腐和褐腐担子菌降解聚乙二醇，聚乙二醇是一种抗非特异性物种攻击的抗真菌聚合物。细胞外氧化剂相比之下，木质部子囊菌不降解聚乙二醇。因此当它们降解木材时不产生这些氧化剂。在大多数情况下，担子菌使用的活性氧仍然是未知的。但羟基自由基（.OH）是可能的参与者，因为存在通过芬顿反应（H2 O2 + Fe 2 + + H+ -> H2O + Fe 3 + + .OH）产生羟基自由基的成熟途径。两个最好的记录真菌途径.OH生产涉及Fe 3+和O-2的细胞外还原纤维二糖脱氢酶或分泌的氢醌，过氧（ROO）。和过氧化氢（.OOH）自由基。虽然它们是较弱的氧化剂，但也可能与木材腐烂有关，因为它们是通过.OH和一些真菌酶的反应产生的。(C)2002年爱思唯尔科技有限公司All rights reserved.
Although many wood decay basidiomycetes secrete oxidative and hydrolytic enzymes that participate in lignocellulose biodedgradation, it is generally recognized now that these enzymes cannot penetrate sound wood, and that fungi must employ smaller agents to initiate decay. Reactive oxygen species (ROS) are likely candidates. and evidence is accumulating that some wood decay fungi produce these oxidants. For example, we have observed that. when they grow on wood, white rot and brown rot basidiomycetes degrade polyethylene glycol, a recalcitrant polymer that resists attack by species other than nonspecific. extracellular oxidants. By contrast, xylariaceous ascomycetes do not degrade polyethylene glycol. and therefore do not produce these oxidants when they degrade wood. The ROS that basidiomycetes employ remain unidentified in most cases. but the hydroxy I radical (.OH) is a likely participant, because there is a well-established pathway for its production via the Fenton reaction (H2O2 + Fe2+ + H+ --> H2O + Fe3+ + .OH). The two best documented fungal pathways for .OH production involve the extracellular reduction of Fe3+ and O-2 by cellobiose dehydrogenase or by secreted hydroquinones, Peroxyl (ROO.) and hydroperoxyl (.OOH) radicals. although they are weaker oxidants, may also be involved in wood decay because they are produced via reactions of .OH and by some fungal enzymes. (C) 2002 Elsevier Science Inc. All rights reserved.