Korean J Parasitol.  2018 Feb;56(1):1-9. 10.3347/kjp.2018.56.1.1.

Pyruvate Protects Giardia Trophozoites from Cysteine-Ascorbate Deprived Medium Induced Cytotoxicity

Affiliations
  • 1Vivekananda College, Thakurpukur, Kolkata-700063, India.
  • 2Division of Parasitology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata-700010, India. sandipanganguly@gmail.com
  • 3Department of Parasitology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
  • 4Collaborative Research Center of Okayama University for Infectious Diseases in India, Kolkata-700010, India.
  • 5Department of Biomedical Chemistry, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.

Abstract

Giardia lamblia, an anaerobic, amitochondriate protozoan parasite causes parasitic infection giardiasis in children and young adults. It produces pyruvate, a major metabolic product for its fermentative metabolism. The current study was undertaken to explore the effects of pyruvate as a physiological antioxidant during oxidative stress in Giardia by cysteine-ascorbate deprivation and further investigation upon the hypothesis that oxidative stress due to metabolism was the reason behind the cytotoxicity. We have estimated intracellular reactive oxygen species generation due to cysteine-ascorbate deprivation in Giardia. In the present study, we have examined the effects of extracellular addition of pyruvate, during oxidative stress generated from cysteine-ascorbate deprivation in culture media on DNA damage in Giardia. The intracellular pyruvate concentrations at several time points were measured in the trophozoites during stress. Trophozoites viability under cysteine-ascorbate deprived (CAD) medium in presence and absence of extracellular pyruvate has also been measured. The exogenous addition of a physiologically relevant concentration of pyruvate to trophozoites suspension was shown to attenuate the rate of ROS generation. We have demonstrated that Giardia protects itself from destructive consequences of ROS by maintaining the intracellular pyruvate concentration. Pyruvate recovers Giardia trophozoites from oxidative stress by decreasing the number of DNA breaks that might favor DNA repair.

Keyword

Giardia lamblia; oxidative stress; cysteine-ascorbate; antioxidant; pyruvate; reactive oxygen species; cytotoxicity

MeSH Terms

Child
Culture Media
DNA Breaks
DNA Damage
DNA Repair
Giardia lamblia
Giardia*
Giardiasis
Humans
Metabolism
Oxidative Stress
Parasites
Pyruvic Acid*
Reactive Oxygen Species
Trophozoites*
Young Adult
Culture Media
Pyruvic Acid
Reactive Oxygen Species
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