Diallyl disulphide depletes glutathione in Candida albicans: Oxidative stress-mediated cell death studied by two-photon microscopy

Katey M. Lemar, Miguel A. Aon, Sonia Cortassa, Brian O'Rourke, Carsten T. Müller, David Lloyd

Research output: Contribution to journalArticle

Abstract

Using two-photon scanning laser microscopy, we investigated the effect of an Allium sativum (garlic) constituent, diallyl disulphide (DADS), on key physiological functions of the opportunistic pathogen Candida albicans. A short 30 min exposure to 0.5 mM DADS followed by removal induced 70% cell death (50% necrotic, 20% apoptotic) within 2 h, increasing to 75% after 4 h. The early intracellular events associated with DADS-induced cell death were monitored with two-photon fluorescence microscopy to track mitochondrial membrane potential (jm), reactive oxygen species (ROS) and NADH or reduced glutathione (GSH) under aerobic conditions. DADS treatment decreased intracellular GSH and elevated intracellular ROS levels. Additionally, DADS induced a marked decrease of jm and lowered respiration in cell suspensions and isolated mitochondria. In vitro kinetic experiments in cell-free extracts suggest that glutathione-S-transferase (GST) is one of the intracellular targets of DADS. Additional targets were also identified, including inhibition of a site or sites between complexes II-IV in the electron transport chain, as well as the mitochondrial ATP-synthase. The results indicate that DADS is an effective antifungal agent able to trigger cell death in Candida, most probably by eliciting oxidative stress as a consequence of thiol depletion and impaired mitochondrial function.

Original languageEnglish (US)
Pages (from-to)695-706
Number of pages12
JournalYeast
Volume24
Issue number8
DOIs
StatePublished - Aug 2007

Keywords

  • Apoptosis
  • Garlic
  • Membrane potential
  • Mitochondria
  • Necrosis
  • Oxidative stress
  • Respiration
  • Yeast

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Genetics

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