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Vedang Diwanji

Vedang Diwanji
Effect of Chitosan on the microbiome of Musca domestica
Program Year: 
Kristen DeAngelis

As a part of the CAFE Summer Scholar Program, I am incredibly grateful to be able to continue my work on an ongoing research project that I have been a part of since Fall 2019. 

The big picture study is trying to understand the effect of Chitosan, a derivative of sugar, on the gut microbiome of Musca domestica (House Fly). House flies, as much as they are a nuisance, are disease vectors and continue to pose a significant public health risk. Meanwhile, ongoing studies are testing the effectiveness of  chitosan, a biodegradable deacylated form of chitin, for its potential use as a bioinsecticide against house flies. Recently, the Stoffolano lab determined that the chitosan diet dramatically reduces fly longevity, but the mechanism of mortality is unknown. The gut microbiome is essential for processing nutrients, and chitosan may inhibit the growth or retention of gut microbes, or change the community structure of the microbiome in a deleterious way, impacting the fly health. My part of the project tests our hypothesis that chitosan acts to reduce the microbial load (quantitative effect) in the gut microbiome as an explanation for chitosan-induced fly mortality. 

I analyzed the quantitative effect in the fly gut microbiome using the technique of Quantitative PCR (QPCR). The QPCR involved targeting a specific region, V3-V4 region, of the 16S rRNA gene using the previously extracted fly DNA from the mortality trial experiment. The QPCR results helped me calculate and analyze the bacterial gene copy number, meaning the amount of bacteria, per fly for each of the diet types. Statistical analysis showed a significant difference and a higher bacterial copy number in flies fed with chitosan, meaning more bacteria, although they weighed significantly lower and appeared smaller than the control flies. These results further pave a path to better understand and observe the trends of the dominant genus of bacteria that vary in each of the diets, and their intrinsic properties in correlation with the fly immunity. This further provides an insight into how chitosan may act as a chemical agent of fly biocontrol, and its specific mechanism of mortality.