Mitochondrial alternative pathways: alternative NADH dehydrogenase and alternative oxidase studies from fungi

• Grant number: 06/04909-0
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2007
• End date: March 31, 2009
• Field of knowledge: Biological Sciences - Biochemistry - Metabolism and Bioenergetics
• Principal Investigator: Sergio Akira Uyemura
• Grantee: Sergio Akira Uyemura
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The saprophytic species Aspergillus fumigatus is a deuteromycete found worldwide. The infection occurs by inhalation of conidia of the fungus, with predominance of respiratory infection, mainly in immunocompromised hosts.Very few is know about it microorganism. Respiration experiments in our lab suggested the presence of mitochondrial alternative pathways such as alternative NADH dehydrogenase and alternative oxidase. Both alternative pathways can be involved at adaptation of microorganism to unstable environments such cold stress, oxidative stress and aerobic conditions, which can modulate the expression or activity of these components. Alternative NADH dehydrogenase from A. fumigatus to others described for plants, fungus, eubacterias and archeobacterias. The activity of this component is stimulated during cell growth, hovewer, the exact function is not clear. Fungi resistance for many drugs that have action on mitochondria has been attributed to the presence of alternative oxidase, which prevents autoxidation of reduced ubiquinone and further reactive oxygen species generation. The gene coding alternative was cloned and sequenced (process 02/01452-5). In the project 05/51677-4, cDNA sequence was clonet at plasmid pET 28a(+) and pYES2 and expressed at heterologous systems, one procariotic, E. coli RosettaTM (DE3)pLysS and other eucariotic, S. cerevisiae INVSc1. In both systems, transformants carrying AOX protein showed a cyanide-insensitive and SHAM-sensitive respiration. It characteristics showed a slight growth in the surviving of yeast in KCN medium.In order to characterized the alternatives pathways, we will verify the alternative NADH dehydrogenase expression pattern in different conditions, as well as it heterologous expression in S. cerevisiae. In addition, alternative oxidase function will be evaluated by iRNA in A. fumigatus. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MAGNANI, TAISA; SORIANI, FREDERICO MARIANETTI; MARTINS, VICENTE DE PAULO; DE FREITAS POLICARPO, ANNA CAROLINA; SORGI, CARLOS ARTERIO; FACCIOLI, LUCIA HELENA; CURTI, CARLOS; UYEMURA, SERGIO AKIRA. Silencing of mitochondrial alternative oxidase gene of Aspergillus fumigatus enhances reactive oxygen species production and killing of the fungus by macrophages. Journal of Bioenergetics and Biomembranes, v. 40, n. 6, p. 631-636, DEC 2008. (03/09781-3, 06/04909-0)