Identifying bacterial pathogens in natural Drosophila populations

Kailene Richbow Dozier, a junior at Virginia Union University, worked with Dr. Kelly Dyer to examine the pathogens present in wild populations of Drosophila.

Abstract: An estimated 70% of the world’s insects are infected with the gram-negative bacteria, Wolbachia pipientis. Wolbachia is known to protect organisms against viral pathogens, however little is known about how it interacts with bacterial pathogens. The aim of this study was to isolate and identify bacterial pathogens within wild, mushroom feeding Drosophila. With this knowledge, we hope that we can aid future research studies trying to understand how Wolbachia increases host resistance to bacterial pathogens as compared to viral pathogens. Two species of flies, Drosophila Putrida and Drosophila Tripunctata were captured from Oconee State Park located in Athens, GA. The captured flies were separated by gender. Female flies were put aside to generate Iso-Female lines, while male flies were homogenized and streaked onto LB agar plates for bacteria growth. Once colonies began to grow after incubation, they were isolated and morphologically identified. 35 bacterial isolates were obtained from the 18 D. Tripunctata flies streaked. 20 bacterial isolates were obtained from the 20 D. Putrida flies streaked. A total of nine bacterial species were identified morphologically, seven of which were shared between the two species of wild flies. Similarities between the abundance of Micrococcus luteus and Enterococcus within both species of flies were observed. D. Tripunctata was seen to slightly differ from D. Putrida by carrying the bacterium Bacillus subtilis and Bacillus megaterium. For future exploration, 16S gene sequencing is needed to accurately confirm the identification of the bacterial pathogens discovered. Afterwards, testing for pathogenicity of the bacterial pathogens needs to be conducted as well as testing for Wolbachia’s interaction with the pathogens.

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