Journal of Microbiology

Research Support, Non-U.S. Gov't

Involvement of Alternative Oxidase in the Regulation of Growth, Development, and Resistance to Oxidative Stress of Sclerotinia sclerotiorum: Ting Xu , Fei Yao , Wu-Sheng Liang , Yong-Hong Li , Dian-Rong Li , Hao Wang , Zheng-Yi Wang; J. Microbiol. 2012;50(4):594-602. Published online August 25, 2012; DOI: https://doi.org/10.1007/s12275-012-2015-7

Abstract: Sclerotinia sclerotiorum is a cosmopolitan, filamentous, fungal pathogen that can cause serious disease in many kinds of crops. Alternative oxidase is the terminal oxidase of the alternative mitochondrial respiratory pathway in fungi and higher plants. We report the presence of this alternative pathway respiration and demonstrate its expression in two isolates of S. sclerotiorum under unstressed, normal culture conditions. Application of salicylhydroxamic acid, a specific inhibitor of alternative oxidase, severely inhibited the mycelial growth of S. sclerotiorum both on potato dextrose agar plates and in liquid culture media. Inhibition of alternative oxidase could influence the growth pattern of S. sclerotiorum, as salicylhydroxamic acid treatment induced obvious aerial mycelia growing on potato dextrose agar plates. Under the treatment with salicylhydroxamic acid, S. sclerotiorum formed sclerotia much more slowly than the control. Treatment with hydrogen peroxide in millimolar concentrations greatly decreased the growth rate of mycelia and delayed the formation of sclerotia in both tested S. sclerotiorum isolates. As well, this treatment obviously increased their alternative pathway respiration and the levels of both mRNA and protein of the alternative oxidase. These results indicate that alternative oxidase is involved in the regulation of growth, development, and resistance to oxidative stress of S. sclerotiorum.

Energy Status of Neurospora crassa Mutant nap in Relation to Accumulation of Carotenoids: Tatyana A. Belozerskaya^ , Tatyana V. Potapova^† , Elena P. Isakova , Eugene I. Shurubor , Ludmila V. Savel'eva , Renata A. Zvyagilskaya; J. Microbiol. 2003;41(1):41-45.

Abstract: N. crassa mutant strain nap showed reduced growth rate, decreased electric membrane potential, and elevated intracellular ATP content in comparison to the wild type. Blue light induced a hyperpolarization of the membrane potential in both strains. The analysis of oxidative and phosphorylation activities of mitochondria isolated from the two strains has revealed that nap utilized more efficient oxidative pathways. The higher intracellular ATP content in the nap was presumably due to impaired transport systems of the plasma membrane, and to a lesser extent to the functioning of the fully competent respiratory chain. The excess ATP possibly accounts for carotenoid accumulation in the mutant.

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