Effects of everyday toxin, titanium dioxide, on Drosophila melanogaster nervous system development

Abstract

Titanium dioxide (TiO2) is a widely used compound found in everything from food packaging to sunscreens. When ingested, TiO2 is readily transported across membranes and efficiently stored within cells. Previous studies showed that exposure to TiO2 results in underdeveloped nervous systems. For our study, we attempted to answer the following question: Will exposing Drosophila melanogaster larvae to TiO2 affect expression of the Neur gene and development of the central nervous system? The Neur gene is crucial during the cell-determination stage of development as its encoded protein helps specify neuroblast development and aids in nervous system and sensory organ development. It was hypothesized that expression of the Neur gene would decrease in Drosophila larvae exposed to TiO2 and that nervous system development would be abnormal compared to control larvae. To test this hypothesis, Drosophila larvae were randomly assigned to either a control group, which was cultured under ideal conditions, or a treatment group, which was exposed to a non-lethal concentration of TiO2. Following exposure, RNA extraction and Reverse Transcription Polymerase Chain Reaction (RT-PCR) was conducted. To quantify nervous system development, Drosophila larvae were subjected to a touch-response assay. Because TiO2 likely damages the Neur gene, it was predicted that Drosophila larvae would show decreased expression of Neur and that they would respond poorly to a mechanical touch-response assay.