Honors Theses
Date of Award
Spring 5-9-2024
Document Type
Undergraduate Thesis
Department
Chemistry and Biochemistry
First Advisor
Paul Boudreau
Second Advisor
Saumen Chakraborty
Third Advisor
Brenton Laing
Relational Format
Dissertation/Thesis
Abstract
Cyanobacteria are an abundant and diverse group of photosynthetic prokaryotes with a long evolutionary history, which presents challenges for comprehensive taxonomic classification. Phylogenies were traditionally constructed based on the highly conserved 16S rRNA gene, but research has increasingly relied upon whole genome sequencing to elucidate evolutionary relationships, despite increased cost and time. In this thesis, publicly available genome sequences of various cyanobacterial strains were utilized to determine if the whole rRNA region, which includes the 16S, 23S, and 5S genes as well as the spacer regions between, could provide accurate, yet cost/time efficient representations of their evolutionary relationships. From phylogenetic trees constructed using the Geneious PrimeⓇ software as well as TYGS, it was determined that an approach using the whole rRNA region remained concordant with 16S data, and therefore was not uniquely informative.
Recognizing the importance of a polyphasic approach, applying classical taxonomy in addition to genomics, this thesis also assessed the salinity tolerance of Boudreau Lab cyanobacterial strains from various freshwater sources in northern Mississippi. Salinity tolerance of cyanobacteria is not only significant for characterizing novel strains, but is also of increasing importance to understand fundamental cyanobacterial biology and its impact on algal bloom formation, an environmental and human threat which has become more prevalent due to climate change and pollution in aquatic environments. From culture inoculations into media prepared over various salt concentrations, it was determined that the majority of Boudreau Lab cyanobacterial strains are able to tolerate some degree of salinization to their environment.
In future work, DNA isolation and genome sequencing of the Boudreau Lab isolates would be necessary to build a phylogeny for our strain library. Salinity tolerance assays for the remaining strains in the Boudreau Lab collection should also be performed, so the upper limit of growth under elevated salt conditions is known for all isolates. Genomic study of the Boudreau Lab collection could also inform any possible genetic basis of salinity tolerance for our isolates by identifying shared genetic information among strains which displayed similar salinity tolerance results.
Recommended Citation
Rowe, Lucie, "Bioinformatic Comparison and Salinity Tolerance of Various Cyanobacterial Strains" (2024). Honors Theses. 3145.
https://egrove.olemiss.edu/hon_thesis/3145
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