Date of Completion

2020

Document Type

Honors College Thesis

Department

Biology

Thesis Type

Honors College, College of Arts and Science Honors

First Advisor

Dr. Sara Helms Cahan

Keywords

cold tolerance, ants, flies, proline, allantoin, rapid cold hardening

Abstract

Temperate-zone insects employ various methods in order to physiologically adapt to harsh environments, such as those with extreme cold weather. In my Honors thesis project, I experimentally explored the effects of two molecules, proline and allantoin, that have been shown to be upregulated in response to cold stress in the temperate ant species Aphaenogaster picea. I artificially enhanced these molecules in their diet and compared their recovery time following cold shock to those maintained under control diets. To further explore this question, I also studied their effects in the genetic model organism Drosophila melanogaster, through both dietary addition of these compounds and eliminating the uric acid pathway, of which allantoin is an intermediate product, with a genetic knock-out. The results indicate that despite allantoin’s demonstrated role in protecting against cellular freezing, proline tended to impede recovery in A. picea and consistently increased recovery time in D. melanogaster, suggesting that it may hinder the ability to recover behaviorally from cold shock. Allantoin had no consistent effect in either species, suggesting it does not play an active role in cold recovery. Moreover, the rosy mutant lacking the entire uric acid pathway had a quicker recovery time than the control, suggesting it may in fact be beneficial not to have the pathway activated. One outcome of this work was to highlight the sensitivity of chill recovery assays to even small changes in protocol and laboratory conditions. Further tests with more reliable protocols may be needed in order to determine the impact of these metabolites on cold tolerance in temperate-zone insects.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Available for download on Tuesday, May 11, 2021

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