Digitized Honors Theses (2002-2017)

Mercy Blalock

Date of Award

5-2014

Document Type

Undergraduate Thesis

Degree Name

BS

Department

Biomedical Sciences

Faculty Mentor

Robin Mockett

Abstract

An organism loses its ability to maintain homeostasis with age, ultimately leading to the organism's death. The loss of the ability to maintain homeostasis is thought to be correlated to an age-related buildup of undegradable, autofluorescent material in the cell, called lipofuscin or age pigment. The hypothesis to be tested in this project was that autofluorescence, possibly associated with lipofuscin, is greater in old than in young tissues isolated from the central nervous system (CNS) of live adult Drosophila melanogaster.

Confocal laser scanning microscopy was used to quantify the autofluorescence of CNS tissues dissected from both young (10 days old) and old (72 days old) flies across a range of excitation and emission wavelengths. Owing to the number of images obtained, quantitative analysis was restricted to optic lobes and an excitation wavelength of 563 nm. Mean intensity of autofluorescence and binary area fractions above a threshold of250 on a gray scale of0 (black) to 4095 (white) were determined at depths of 2, 4, and 6 µm into the tissue. The young flies had a greater mean intensity of autofluorescence than old flies for all emission wavelengths from 430-750 run. The binary area fractions of the same images were greater for young versus old flies at most emission wavelengths. Both mean intensity and binary area fraction were highest for emission in the 10 nm interval immediately beyond the excitation wavelength (570-580 run). Mean intensity and binary area fraction both decreased as depth within the tissue increased. The overall conclusion for this project is that autofluorescence did not increase as a function of age in the central nervous system of D. melanogaster when excited at 563 nm.

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