Student Research Projects

A comparison of the cultivable bacteria from surface-sterilized wolbachia-infected and wolbachia-free drosophila melanogaster

Student Keane Dye ‘16 (Biology and Chemistry)
Faculty Mentor(s)
Department Biology
Course Biology 489: Research in the Natural Sciences

Abstract

It has been shown that the environments that Dorsophila melanogaster inhabit are a major contributor to the development and maintenance of the organism’s microbiome. However, few studies have examined the effect of the endosymbiotic bacteria Wolbachia on the microbiome of Drosophila melanogaster. Previous work by Amanda Hyre demonstrated some potential alterations of the microbiome using a metagenomic-based analysis. The purpose of this project was to determine if Wolbachia has any effect on the microbiome of Drosophila melanogaster, using culture-dependent methods. This was done by determining the total bacteria that could be isolated from both Wolbachia positive and negative flies. Dilutions of whole fly homogenates from surface-sterilized infected and uninfected flies were spread on standard culture media and the bacterial colonies were counted to give an estimate of the total number and types of bacteria found in each fly. As reported previously, the overall diversity of bacterial types is quite low. The results suggest that Wolbachia-positive flies harbor a greater number of bacteria than uninfected flies. While the types of bacteria isolated from each strain of fly were similar, there may be consistent differences in the proportions of the bacterial species seen between infected and uninfected flies. Further studies will need to verify these preliminary results. It is not currently known how the presence of the Wolbachia endosymbiont may alter the total number of bacteria or the proportions of the bacterial types recovered.