What Effects do Silver Nanoparticles Have on Drosophila melanogaster Larvae with Respect to Stress Response and Microbial Intestinal Composition?
Silver nanoparticles (AgNPs) have been shown to be highly toxic to certain organisms and can induce stress in cells. The purpose of this study is twofold: first, to examine the stress response to AgNP exposure on Drosophila melanogaster (fruit fly) larvae, and secondly, to determine if exposure to AgNPs alters the intestinal bacterial composition. To answer these questions, fruit flies were grown on food mixed with AgNPs. Larvae were monitored for their ability to escape from heat stress and their climbing ability before metamorphosis into pupae. Larval wandering behaviour was examined by devising a test to determine if they could crawl their way back to food. In order to examine the flora in the digestive tract, DNA was isolated from dissected larval intestines, purified and then a relatively conserved portion of the bacterial DNA was amplified. These samples were then sent for pyrosequencing, which is a technique that will allow us to examine the composition of the intestinal microbial population. Preliminary results have been mixed. There has been some suggestion of a stress response, but this has not been very consistent. Therefore, more experiments need to be done. However, the bacterial population of the gut does seem to change after the treatment, indicating that AgNP exposure results in altered microbial composition in D. melanogaster intestines. It is hoped that this research will help elucidate our understanding of the impact NPs have on organisms, which is highly relevant because of the high prevalence of NPs in consumer and medicinal materials.