Date of Defense

5-1-2026

Date of Graduation

5-2026

Department

Biological Sciences

First Advisor

Silvia Rossbach

Second Advisor

Megan Parsell

Third Advisor

Pamela Hoppe

Keywords

lanthanides, xoxF5, methanol dehydrogenase, petroleum contamination, soil microbiology, PCR, methylotroph

Abstract

Lanthanide-dependent methanol dehydrogenase, encoded by the xoxF gene, is an important enzyme in the carbon metabolism of methylotrophic and methanotrophic bacteria. The five phylogenetically distinct clades of xoxF include clade 5 (xoxF5), which is the most widely distributed and found in a range of environmental conditions, both marine and terrestrial. Although there is increasing awareness of their ecological value, the occurrence of xoxF genes in petroleum contaminated soils remains largely unexplored. This study aimed to detect lanthanide-dependent xoxF5 genes in sediment DNA previously collected from a petroleum-contaminated soil core at the National Crude Oil Spill Fate and Natural Attenuation Research Site near Bemidji, Minnesota. PCR amplification of 27 depth-resolved samples spanning the surface to the oil and water table interface was performed using degenerate xoxF5-specific primers designed by Taubert et al. (2015). Amplification of 16S rRNA genes was used as a control to assess DNA presence and quality. The results of gel electrophoresis indicated that xoxF5 was amplified in various samples distributed at different depths, with positive results in the upper core parts and in samples collected across multiple depths within core. The 16S rRNA gene control supported the quality and amplifiability of the extracted DNA in the selected samples. These findings provide evidence for the presence of lanthanide-dependent methylotrophic bacteria in terrestrial petroleum-contaminated soils.

Access Setting

Honors Thesis-Restricted

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