Presentation Title

Characterization of temperature adaptation of allelic variants of Alcohol Dehydrogenase Enzyme in Drosophila Melanogaster

Abstract

Heterothermic ectotherms, such as Drosophila melanogaster, are particularly threatened by increasing global temperatures. Researching the thermal stability of enzymes critical to their metabolic function will reveal critical information about how they might respond to these temperature changes. This project will analyze the differences in the thermal stability of Alcohol Dehydrogenase (ADH) enzyme in Drosophila melanogaster. The ADH enzyme has two alleles, ADHf (fast) and ADHS (slow). These allelic variants are found to exist on a latitudinal cline, with the ADHf allele more common at higher latitudes in cooler climates and the ADHs allele more common at lower latitudes with warmer climates. This experiment will test how these alleles respond to a heat stress in their environment by heating the enzyme solution and comparing the residual activity periodically after 0 to 90 minutes of incubation and measure how the Michaelis-Menten Constant (Km) changes with temperature from 18°C to 38°C. In addition to measuring the enzyme activity of both ADHf and ADHs homozygotes, the residual activity of populations from Chiapas, Mexico and Vermont, USA was measured. With comparisons of the residual activity and the apparent Km determinations of these enzyme alleles, I determined that both are unique biochemical characteristics of allelic variant of ADH. Because thermal stability and apparent Km are significantly different among populations and seemingly contradict each other, more studies are needed to understand how natural selection drives the evolution of allelic variants of the ADH enzyme.

Primary Faculty Mentor Name

Brent Lockwood

Status

Undergraduate

Student College

College of Arts and Sciences

Program/Major

Biological Science

Primary Research Category

Biological Sciences

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Characterization of temperature adaptation of allelic variants of Alcohol Dehydrogenase Enzyme in Drosophila Melanogaster

Heterothermic ectotherms, such as Drosophila melanogaster, are particularly threatened by increasing global temperatures. Researching the thermal stability of enzymes critical to their metabolic function will reveal critical information about how they might respond to these temperature changes. This project will analyze the differences in the thermal stability of Alcohol Dehydrogenase (ADH) enzyme in Drosophila melanogaster. The ADH enzyme has two alleles, ADHf (fast) and ADHS (slow). These allelic variants are found to exist on a latitudinal cline, with the ADHf allele more common at higher latitudes in cooler climates and the ADHs allele more common at lower latitudes with warmer climates. This experiment will test how these alleles respond to a heat stress in their environment by heating the enzyme solution and comparing the residual activity periodically after 0 to 90 minutes of incubation and measure how the Michaelis-Menten Constant (Km) changes with temperature from 18°C to 38°C. In addition to measuring the enzyme activity of both ADHf and ADHs homozygotes, the residual activity of populations from Chiapas, Mexico and Vermont, USA was measured. With comparisons of the residual activity and the apparent Km determinations of these enzyme alleles, I determined that both are unique biochemical characteristics of allelic variant of ADH. Because thermal stability and apparent Km are significantly different among populations and seemingly contradict each other, more studies are needed to understand how natural selection drives the evolution of allelic variants of the ADH enzyme.