Date of Award

5-2017

Degree Type

Honors College Thesis

Department

Chemistry and Biochemistry

First Advisor

Shahid Karim, Ph.D.

Advisor Department

Biological Sciences

Abstract

Selenium (Se) is an element recognized as an essential micronutrient in eukaryote organisms. Selenoproteins contain selenium as selenocysteine, the 21st amino acid. Selenium plays a role in cell growth and functioning. At low concentrations, it can induce growth and at high concentrations, it can cause a cell to stop growing and potentially have toxic effects on the cell and organism. When selenium levels are high, oxidative stress results by the production of reactive oxidative species. Selenoproteins, however, can aid the antioxidant response in the cell. Ticks are arthropods of interest, as they are one of few that contain many selenogenes, possibly the reason for their robust antioxidant system. Ticks are obligate hematophagous ectoparasite and require this strong and organized antioxidant system for when oxidative stress is induced during blood feeding and digestion. In this study, the effects of sublethal sodium selenite concentration on the female Amblyomma maculatum tick’s antioxidant system were investigated. The oxidative stress analysis of ticks injected with sublethal concentration of sodium selenite (0.1μM Na2SeO3) compared with 1X PBS injected Amblyomma female ticks. Once tissues were obtained, transcriptional gene expression was performed for all antioxidants including selenogenes. The transcript level of selenogene M (SelM), and selenogene N (SelN) revealed up-regulation. A lipid peroxidation (MDA assay), and fluorescent assays were utilized to quantify the relative oxidative stress and visually examined oxidative stress effects on tick tissues. Oxidative stress was illustrated in the assay and confocal and gave insight on how tick antioxidant system responds to a sublethal sodium selenite concentration. The outcomes could lead to understanding tick physiology and give insight on tick antioxidant system.

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