Physical-chemical study of fungicidal activity of amphiphilic chitosan derivatives against fungi of the genus Aspergillus: interaction with model membranes

• Grant number: 13/16021-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: October 01, 2013
• End date: February 28, 2015
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Vera Aparecida de Oliveira Tiera
• Grantee: Mirelle Takaki
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil

Abstract

The fungi from genus Aspergillus, particularly Aspergillus flavus and Aspergillus parasiticus, are considered an important problem for the production and storage of grains, since besides of inducing the degradation and contamination of food, some strains produce very harmful mycotoxins. In order to control the development of these microorganisms, the use of low cost and environmentally safe natural products, such as chitosan and its derivatives has been emphasized. Thus, this project proposes the synthesis and characterization of quaternary amphiphilic derivatives of chitosan with a fixed hydrophobic content (5 %) and increasing proportions of permanent positive charges in the polymer chain at neutral pH. The derivatives will be synthesized using as starting material deacetylated chitosan in a two steps process: the first is a reductive aminationreaction with dodecylaldehyde followed by substitution reaction with quaternary amino groups using pentyltrimethylammonium bromide. The derivatives will be characterized by H1NMR, viscosity measurements and gel permeation chromatography (GPC). In addition, the antifungal activity of the derivatives against the fungi A. flavus and/or A. parasiticus will be evaluated and mechanism of action will be investigated using two methodologies: i) The study of the interaction of derivatives with model membranes with controlled surface potential and ii) Fluorescent labeling of the derivatives and the study of their interaction with the fungi Aspergillus flavus and/or Aspergillus parasiticus via optical, confocal and transmission electronic microscopy. (AU)

Academic Publications

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

TAKAKI, Mirelle. Estudo físico-químico da atividade fungicida de derivados anfifílicos de quitosana contra fungos do gênero Aspergillus : interação com modelos de membranas. 2015. Master's Dissertation - Universidade Estadual Paulista (Unesp). Instituto de Biociências Letras e Ciências Exatas. São José do Rio Preto São José do Rio Preto.