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BioMed Research International
Volume 2014 (2014), Article ID 704937, 11 pages
Research Article

Differential Expression and Immunolocalization of Antioxidant Enzymes in Entamoeba histolytica Isolates during Metronidazole Stress

1School of Life Sciences, Jawaharlal Nehru University, New Delhi 110070, India
2School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110070, India

Received 27 February 2014; Revised 29 April 2014; Accepted 13 May 2014; Published 12 June 2014

Academic Editor: Miriam Rodriguez-Sosa

Copyright © 2014 Lakshmi Rani Iyer 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.


Entamoeba histolytica infections are endemic in the Indian subcontinent. Five to eight percent of urban population residing under poor sanitary conditions suffers from Entamoeba infections. Metronidazole is the most widely prescribed drug used for amoebiasis. In order to understand the impact of metronidazole stress on the parasite, we evaluated the expression of two antioxidant enzymes, peroxiredoxin and FeSOD, in Entamoeba histolytica isolates during metronidazole stress. The results reveal that, under metronidazole stress, the mRNA expression levels of these enzymes did not undergo any significant change. Interestingly, immunolocalization studies with antibodies targeting peroxiredoxin indicate differential localization of the protein in the cell during metronidazole stress. In normal conditions, all the Entamoeba isolates exhibit presence of peroxiredoxin in the nucleus as well as in the membrane; however with metronidazole stress the protein localized mostly to the membrane. The change in the localization pattern was more pronounced when the cells were subjected to short term metronidazole stress compared to cells adapted to metronidazole. The protein localization to the cell membrane could be the stress response mechanism in these isolates. Colocalization pattern of peroxiredoxin with CaBp1, a cytosolic protein, revealed that the membrane and nuclear localization was specific to peroxiredoxin during metronidazole stress.