Francesca De Martini

Areas of Work

Isavannah Reyes, Alvaro Mendoza, and Francesca De Martini - Microbial Analysis of Pool Water (Spring 2020)

The molecular analysis of microorganisms present in water samples is an important process used not only in water treatment but also in many areas of biology research. In this study, we investigated the microbial diversity in a private swimming pool located in Mesa, Arizona infested by algae.

The microbial diversity of two different samples was determined using the 16S rRNA gene marker. After performing DNA extraction, the samples were sequenced using Miseq 150X2 Illumina Next-Generation platform and analyzed using QIIME 2 software.

We found that the majority of sequences clustered within two microbial groups: a eukaryotic photosynthetic organism and a pinnacle-forming cyanobacterium. As expected, the photosynthetic protist, Coccomyxa Subellipsoidea, was found in both samples and made up 80% of the total microbial community. On the other hand, we were surprised to find sequences of Leptolyngbya sp., a cyanobacterium that is capable to perform anoxygenic photosynthesis and that is found in nature in microbial mat covering sediments surface of microoxic and sulfidic waters (Hamilton et al., 2018).

These results further highlight the need to characterize the diversity of microbial communities in private swimming pools to be able to create more efficient swimming pool treatments.

Ana Gabriela Mansilla, David Rainford, Isavannah Reyes, Alvaro Mendoza, and Francesca De Martini - Microbial Diversity in the Musk of Garter Snakes (Fall 2020)

Common garter snakes (Thamnophis sirtalis) are snake species endemic to regions of North America (Gleaton, 2003). Garter Snakes are generally harmless, small to medium-sized snakes belonging to the genus Thamnophis. Snakes fabricate musk, which is a defense mechanism that allows snakes to warn off predators and threats without having to fight or use venom. In this study, the data was provided by Parker et al. from the Department of Biology at the James Madison University. Samples from the cloaca of T. sirtalis subjects were taken to perform DNA extractions. The 16S rRNA region was amplified with PCR and sequenced using Illumina MiSeq. The sequences were analyzed for microbial characterization using DNA Subway (CyVerse, 2020). We found that the female garter snakes microbiome was more varied and complexed, showing a large presence of Firmicutes, compared to the male microbiome, where we found a larger presence of both Proteobacteria and unknown bacteria.