Document Type
Article
Publication Date
6-1-2016
Department
Biological Sciences
School
Biological, Environmental, and Earth Sciences
Abstract
As obligate blood‐sucking ectoparasites, to avoid tissue damage, ticks must neutralize the reactive oxygen species (ROS) generated from uptake and digestion of a bloodmeal. Consequently, ticks utilize a battery of antioxidant molecules, including catalase (CAT), an enzyme that converts hydrogen peroxide (H2O2) into water and oxygen. Here, we investigated the tick antioxidant machinery by exogenous injection of sublethal doses of H2O2 or paraquat. The relative transcript levels of selected Amblyomma maculatum antioxidant targets in tissues were determined by quantitative reverse transcriptase PCR following treatment. The results showed 2–16‐fold increases in target antioxidant gene transcripts, signifying the ability of Am. maculatum to regulate its antioxidant machinery when exposed to increased ROS levels. Next, RNA interference was used to determine the functional role of CAT in haematophagy, redox homeostasis and reproductive fitness. CAT gene silencing was confirmed by transcript depletion within tick tissues; however, CAT knockdown alone did not interfere with tick haematophagy or phenotype, as confirmed by the resulting differential expression of antioxidant genes, thereby indicating an alternative mechanism for ROS control. Interestingly, double stranded RNA of CAT gene (dsCAT) and the CAT inhibitor, 3‐aminotriazole, together reduced tick reproductive fitness via a marked reduction in egg mass and larval eclosion rates, highlighting a role for CAT in tick redox‐homeostasis, making it a potential target for tick control.
Publication Title
Insect Molecular Biology
Volume
25
Issue
3
First Page
283
Last Page
294
Recommended Citation
Kumar, D.,
Budachetri, K.,
Meyers, V.,
Karim, S.
(2016). Assessment of Tick Antioxidant Responses to Exogenous Oxidative Stressors and Insight Into the Role of Catalase in the Reproductive Fitness of the Gulf Coast Tick, Amblyomma maculatum. Insect Molecular Biology, 25(3), 283-294.
Available at: https://aquila.usm.edu/fac_pubs/15007
Comments
This is the peer reviewed version of the following article: "Assessment of Tick Antioxidant Responses to Exogenous Oxidative Stressors and Insight Into the Role of Catalase in the Reproductive Fitness of the Gulf Coast Tick, Amblyomma maculatum", which has been published in final form at https://doi.org/10.1111/imb.12218. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.