Table of Contents
Journal of Mycology
Volume 2014 (2014), Article ID 178274, 9 pages
http://dx.doi.org/10.1155/2014/178274
Research Article

Investigating Acid Stress Response in Different Saccharomyces Strains

1Núcleo de Pesquisas em Ciências Biológicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, 35400-000 Ouro Preto, MG, Brazil
2Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Campus Universitário, 30171-970 Belo Horizonte, MG, Brazil
3LBCM, Instituto de Ciências Exatas e Biológicas, Campus Morro do Cruzeiro, 35400-000 Ouro Preto, MG, Brazil

Received 3 February 2014; Accepted 1 April 2014; Published 17 April 2014

Academic Editor: Praveen Rao Juvvadi

Copyright © 2014 Rogelio Lopes Brandão et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Yeast cells need to respond to a variety of stresses found in such different conditions as gastrointestinal tract after probiotic ingestion or fermentation vat during ethanol production. In the present study, H+ neutralisation capacity, membrane fatty acid composition, H+-ATPase activity, and cytosolic Ca2+ concentration were evaluated in yeast cells used for probiotic (Saccharomyces boulardii) and laboratory (Saccharomyces cerevisiae W303) purposes, as well as in some W303 mutant strains for ENA1 gene and S. cerevisiae BY4741. Results show that the H+ internal concentration of yeast is regulated by several systems, including the plasma membrane H+-ATPase, and that Ena1p has an important but undefined role in the cellular response to acid. Membrane fatty acid composition of S. cerevisiae W303 strain was affected by exposure to acidic pH, but the presence of 86 mM NaCl prevented this effect, whereas membrane fatty acid composition of S. boulardii was unaffected by acidic pH. We also demonstrated that the acid stress response is dependent on calcium metabolism and blocked by FK 506.