Date of Award

Spring 5-15-2016

Document Type

Thesis

Degree Name

Bachelor of Science (BS)

Department

Biology

College

College of Science

First Advisor

Fang Ju Lin

Abstract/Description

Human Alzheimer's disease (AD) is the most prevalent and lethal neurodegenerative disease; it involves the accumulation of neurofibrillary tangles, loss of synapses and neurons in specific areas of the brain, and the presence of extracellular amyloid plaques, particularly Amyloid beta-42 (AP-42). In this study, two Drosophila transgenic fly lines carrying either elav-GAL4 driver or UAS-AP-42 transgene, were crossed to generate AD flies that expressed low levels of human Ap-42. Male AD flies (experimental) and elav-GAL4 flies (as parental control without AP-42) were tested for learning and short-term memory using the courtship suppression assay (Siegal and Hall, 1979). The courtship suppression assay includes "training" and "testing" periods, where male flies rejected by a previously mated female during training will retain the memory and therefore exhibit less courtship behaviors in testing period. First, a single virgin male was assigned to one of three training conditions: paired with a previously mated (trainer) female (experimental condition), a virgin female, or no female (sham control). After one hour of training, all males were transferred and paired with virgin females for ten minutes. Independent raters reviewed the training and testing videos and calculated courtship indices (CI) reflecting the amount of time males engaged in characteristic courtship behaviors (ex. orientation, wing vibration, tapping). Both 4-6 days-old elav-GAL4 and AD males exhibited less courtship behaviors towards mated females, suggesting the efficacy of training. In addition, trained elav-GAL4 males had a lower average CI than the sham control in testing, indicating their short term memory is intact. However, the average testing CI for 4-6 days-old trained AD males was similar compared to their sham control group. Our results showed that four-to-five days-old AD males already exhibited deficits in short-term memory.

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