锰和色氨酸组合对丝状真菌微紫青霉菌抗氧化酶及多酚氧化酶活性的影响

Effects of Combination of Manganese and Tryptophan on Activities of Antioxidant Enzymes and Polyphenol Oxidase of Filamentous Fungus Penicillium janthinellum

Cu是一种十分常见的重金属,在高浓度下铜对生物体产生毒害。丝状真菌是重要的一类真核微生物资源。超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD),以及电子传递相关的多酚氧化酶(PPO)在非生物胁迫下的抗氧化胁迫中起重要作用。锰(Mn)是SOD的重要组成成份,铜(Cu)是PPO的必须组成成份。色氨酸(Trp)是一类重要的非酶抗氧化氨基酸。但是目前并不清楚Mn、Trp以及Mn-Trp组合对这些酶系的酶活性的影响。我们对在Cu胁迫下,以及在添加外源性Mn和Trp条件下的抗重金属能力很高的微紫青霉菌(Penicillium janthinellum)GXCR菌株及其紫外诱变的Cu抗性降低突变体SM1的上述酶活性变化进行了研究,结果表明,外源性单独添加Mn和Trp或者同时添加Mn和Trp能够提高抗氧化酶SOD,CAT和POD活性,也能增强PPO活性,但是,依据不同菌株的Cu抗性的背景的差异或者提高或者抑制酶活性。该研究结果对进一步深入研究抗氧化酶系-Mn-Trp相互作用下的真菌的Cu抗性机制提供了线索。

Copper （Cu） is a very common heavy metal, which is toxic towards the living organisms at high concentrations. Filamentous fungi is a class of important eukaryotic microorganism resources. Superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD）, and electron transfer-related polyphenol oxidase （PPO） play important roles in abiotic stress resistance. Manganese （Mn） is an important composition of SOD, and Cu is an essential constituent ofPPO. Tryptophan （Trp） is a class of important non-enzymatic antioxidant amino acids. However, it has been unclear about effects of Mn, Trp, and Mn-Trp combination on activities of these enzymes. In this study, we investigated the changes in activities of the enzymes in the mycelia of Penicillium janthinellum strains GXCR of high heavy metal resistance and its ultraviolet mutagenesis-resulted Cu resistance-reducing mutant SM1. The results showed that exogenously adding Mn and Trp alone or at the same time adding Mn and Trp could enhance activities of antioxidant enzymes SOD, CAT and POD, PPO, but, such effects was to enhance or inhibit the enzyme activities depending on the differences in the Cu resistance background levels of different strains. These results provided a clue for further studies of fungal Cu resistance mechanisms by antioxidant enzymes-Mn-Trp interactions.