<p dir="ltr"><i>Serratia marcescens </i>is a bacterium with a ubiquitous environmental distribution and the ability to cause opportunistic infections. This research explores three different group behaviors in <i>S. marcescen</i>s. These are biofilm formation, microbial hitchhiking, and responses to cannabinoid-induced stress. To study biofilm development, we used a crystal violet assay to measure biofilm and compared that to the bacterial growth of those cultures. We looked at the role of nutrients and temperature in biofilm produced by <i>S. marcescens</i> and tested four <i>S. marcescens</i> strains. We found that there were differences in the ratio of biofilm to growth when <i>S. marcescens</i> was grown in different media. The exact relationship between temperature and media composition requires more information than could be attained from these studies. Next, we wanted to investigate whether <i>S. marcescens</i> could also utilize movement of other, more highly motile species of bacteria through a process called microbial hitchhiking. <i>S. marcescens</i> was grown with a highly motile <i>Paenibacillus</i> sp. isolate. <i>S. marcescens</i> was tracked by the red pigment that it produces. It was observed that <i>S. marcescens</i> consistently spread farther across a surface when it was co-cultured with <i>Paenibacillus</i> sp. than when grown alone. This was repeated with three other <i>S. marcescens</i> strains and three different species of <i>Paenibacillus.</i><i> </i>Hitchhiking behavior was observed in all cases. To understand the mechanism by which <i>S. marcescens</i> hitchhikes on <i>Paenibacillus </i>spp., a <i>S. marcescens </i>flagellar mutant was used. Even in the absence of a flagellum, <i>S. marcescens</i> was still able to hitchhike implying that another mechanism must be involved. Finally, we evaluated the response of <i>S. marcescens </i>to cannabidiol (CBD) a phytocannabinoid with antimicrobial and antibiofilm properties, though it has limited potency against Gram-negative bacteria like <i>S. marcescens</i>. We found that CBD did not kill <i>S. marcescens </i>nor did it affect its biofilm development. Interestingly, <i>S. marcescens </i>cultures showed enhanced pigment production in response to high-dose CBD exposure compared to vehicle controls. This response was also observed with exposure to three additional phytocannabinoids. Results from these studies add to our understanding of how <i>S. marcescens</i> can access new areas and persist in a broad range of environments.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/25738977 |
| Date | 03 May 2024 |
| Creators | Sarah Joyce Rosser (18495273) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Rosser_thesis_pdf/25738977 |
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