Document Type


Date of Award



College of Science, Engineering, and Technology (COSET)

Degree Name

Ph.D. in Environmental Toxicology

Committee Chairperson

Ayodotun Sodipe Shishir Shishodia, Sonya Good, Alamelu Sundaresan, Mofolorunso Enigbokan

Committee Member 1

Shishir Shishodia

Committee Member 2

Sonya Good

Committee Member 3

Alamelu Sundaresan

Committee Member 4

Mofolorunso Enigbokan


Cadmium, HSP-70, Hypsibius Exemplaris, Reactive Oxygen Species, Tardigrades


Heavy metals such as Cadmium are known stressors in aquatic environments due to being persistent in nature and the ability to bioaccumulate in organisms. Cadmium ranks 7th on the Agency for Toxic Substance and Disease Registry’s 2019 Substance Priority List. It is also listed as a substance of very high concern by the European Chemicals Agency. Thus, it is considered one of the most important environmental and occupational pollutants existing. This study aimed at investigating the cellular responses to the heavy metal Cadmium (Cd) and observe the processes that are involved in its detoxification. Tardigrade specimens (Hypsibius exemplaris) were exposed to varying concentrations of cadmium ranging from 1mg/l to 15mg/l at 6, 12 and 24-hours intervals. The expressions of reactive oxygen species (ROS) and antioxidant enzymes (superoxide dismutase, catalase and glutathione-s-transferase) were measured after cadmium exposure. Tardigrade viability was also assessed based on observed locomotive movements of the tardigrades. The results of this study indicate that antioxidant defense components in the tardigrade Hypsibius exemplaris are significantly affected by cadmium toxicity. The viability analysis showed that the in vivo acute exposures decreased starting from the 5 mg/L concentration over a 24-hours period. The results show that cadmium can induce the excessive production of reactive oxygen species (ROS) resulting in oxidative stress as ROS was statistically significantly higher than control after 24 hours of cadmium exposure (p

Included in

Biology Commons


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