Open AccessAn alternative respiratory pathway on C andida krusei : implications on susceptibility profile and oxidative stress
Author(s) -
CostadeOliveira Sofia,
SampaioMarques Belém,
Barbosa Matilde,
Ricardo Elisabete,
PinaVaz Cidália,
Ludovico Paula,
Rodrigues Acácio G.
Publication year - 2012
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2012.00789.x
Subject(s) - biology , candida krusei , oxidative stress , microbiology and biotechnology , respiratory system , candida albicans , biochemistry , anatomy , candida tropicalis
Our aim was to detect the presence of an alternative oxidase ( AOX ) in C andida krusei clinical strains and its influence on fluconazole susceptibility and in reactive oxygen species ( ROS ) production. C andida krusei clinical isolates were tested to evaluate the presence of AOX . D ebaromyces hansenii 2968 ( AOX positive) and S accharomyces cerevisiae BY 4742 ( AOX negative) were used as control strains. Measurements of oxygen consumption were performed in the presence of 1 mM KCN , an inhibitor of the classical respiratory chain, and 5 mM salicylhydroxamic acid ( SHAM ). AOX expression was monitored by Western blotting using an AOX monoclonal antibody. Interactions between fluconazole and SHAM were performed using checkerboard assay. ROS production was evaluated in the presence of SHAM plus fluconazole, H 2 O 2 , menadione, or plumbagin. AOX was present in all C . krusei tested. The combination of fluconazole with SHAM resulted in an indifferent effect. In the presence of SHAM , the treatment with ROS inductors or fluconazole increased ROS production, except in the AOX ‐negative strain. An alternative respiratory pathway resistant to cyanide is described for the first time as a characteristic of C . krusei species. This AOX is unrelated to fluconazole resistance; however, it protects C . krusei from oxidative stress.