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Divergent Transcriptional Responses to Physiological and Xenobiotic Stress in Giardia duodenalis
- Source :
- Antimicrobial Agents and Chemotherapy; July 2016, Vol. 60 Issue: 10 p6034-6045, 12p
- Publication Year :
- 2016
-
Abstract
- ABSTRACTUnderstanding how parasites respond to stress can help to identify essential biological processes. Giardia duodenalisis a parasitic protist that infects the human gastrointestinal tract and causes 200 to 300 million cases of diarrhea annually. Metronidazole, a major antigiardial drug, is thought to cause oxidative damage within the infective trophozoite form. However, treatment efficacy is suboptimal, due partly to metronidazole-resistant infections. To elucidate conserved and stress-specific responses, we calibrated sublethal metronidazole, hydrogen peroxide, and thermal stresses to exert approximately equal pressure on trophozoite growth and compared transcriptional responses after 24 h of exposure. We identified 252 genes that were differentially transcribed in response to all three stressors, including glycolytic and DNA repair enzymes, a mitogen-activated protein (MAP) kinase, high-cysteine membrane proteins, flavin adenine dinucleotide (FAD) synthetase, and histone modification enzymes. Transcriptional responses appeared to diverge according to physiological or xenobiotic stress. Downregulation of the antioxidant system and α-giardins was observed only under metronidazole-induced stress, whereas upregulation of GARP-like transcription factors and their subordinate genes was observed in response to hydrogen peroxide and thermal stressors. Limited evidence was found in support of stress-specific response elements upstream of differentially transcribed genes; however, antisense derepression and differential regulation of RNA interference machinery suggest multiple epigenetic mechanisms of transcriptional control.
Details
- Language :
- English
- ISSN :
- 00664804 and 10986596
- Volume :
- 60
- Issue :
- 10
- Database :
- Supplemental Index
- Journal :
- Antimicrobial Agents and Chemotherapy
- Publication Type :
- Periodical
- Accession number :
- ejs40066917
- Full Text :
- https://doi.org/10.1128/AAC.00977-16