Mechanistic study of the photodynamic inactivation of pathogenic fungi with novel phenothiazinium photosensitizer

• Grant number: 14/04162-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: July 01, 2014
• End date: February 29, 2016
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Gilberto Úbida Leite Braga
• Grantee: Júlia Cunha Gonzales
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The increasing emergence of fungicide tolerance among many species of human and plant-pathogenic fungi has stimulated the development of different approaches to control this group of pathogens. Antifungal photodynamic treatment (APDT) is a promising alternative to conventional fungicides that can be used to treat localized mycoses in humans as well to reduce the population of pathogenic fungi in the environment. The process involves the use of a non-toxic light activated photosensitizer (PS) which selectively accumulates into the target-cells. In the presence of oxygen, the excited state PS induces the formation of several reactive oxygen species that kill the microorganism without significant damage to the host. Although very promising, the use of APDT to treat mycosis has not been much developed and APDT has not been used to control phytopathogenic species. The objectives of the present study are: (1) to identify novel phenothiazinium PS more effective for the APDT of the phytopathogenic fungus Colletotricum acutatum and the human pathogenic fungus Trichophyton rubrum; (2) to determine the mechanism of action of the novel PS in metabolically active structures such as hyphae as well as in quiescent structures such as conidia and apressorium and to evaluate if repeated APDT can select tolerant strains in both species. The expected contributions include: (1) the improvement of the mechanistic understanding of APDT with the novel PS on the specialized structures of C. acutatum and T. rubrum, (2) the supply of the necessary foundation for the use of APDT to control phytopathogenic fungi e (3) determining whether successive cycles of APDT can select tolerant strains in pathogenic fungi.

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)

GONZALES, JULIA C.; BRANCINI, GUILHERME T. P.; RODRIGUES, GABRIELA B.; SILVA-JUNIOR, GERALDO JOSE; BACHMANN, LUCIANO; WAINWRIGHT, MARK; BRAGA, GILBERTO U. L.. Photodynamic inactivation of conidia of the fungus Colletotrichum abscissum on Citrus sinensis plants with methylene blue under solar radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY, v. 176, p. 54-61, NOV 2017. (14/04162-8, 12/15204-8, 16/11386-5)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

GONZALES, Júlia Cunha. In vitro and in planta antimicrobial photodynamic treatment of Colletotrichum acutatum with phenothiazinium photosensitizers. 2016. Master's Dissertation - Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC) Ribeirão Preto.