Keywords
Clostridioides difficile physiology; Formate metabolism; Gas production
Abstract
Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacterium and the leading cause of antibiotic-associated diarrhea worldwide. During infection, antibiotic-induced disruption of the gut microbiota allows C. difficile to colonize and proliferate. Motility, enabled by flagella, is an important factor in colonization and may be influenced by metabolic activity. Recent experiments have observed gas production during C. difficile motility assays, but the biochemical basis of this phenomenon remains unknown. Because gas formation in other bacteria such as E. coli involves the formate hydrogenlyase complex and the enzyme formate dehydrogenase (FDH), we hypothesize that C. difficile gas production under motility conditions is mediated by FDH activity. To explore this relationship, gas production and motility were examined in three C. difficile strains: the wild-type R20291 strain, an fdhF knockout strain, and a selAB knockout strain that disrupts selenocysteine incorporation and thereby inactivates FDH and other selenoproteins. Experiments were performed in BHIS medium with varying agar concentrations and with or without formate supplementation to assess conditions influencing gas production. Motility was further tested on BHIS plates containing 0.3% agar, also supplemented with or without formate. Gas production was observed in nearly all conditions for all strains, though the selAB strain showed reduced activity in some conditions. Similarly, motility assays demonstrated that all strains remained motile, with the selAB knockout exhibiting noticeably smaller motility zones and the fdh knockout displaying motility comparable to or greater than the wild type. These results indicate that neither FDH nor selenoprotein dependent metabolism is solely responsible for supporting gas production or motility under the tested conditions.
Thesis Completion Year
2025
Thesis Completion Semester
Fall
Thesis Chair
Self, William
College
College of Medicine
Department
Burnett School of Biomedical Sciences
Thesis Discipline
Microbiology
Language
English
Access Status
Open Access
Length of Campus Access
None
Campus Location
Orlando (Main) Campus
STARS Citation
Gupta, Ria D., "Investigation of Hydrogen Gas Production and Motility in ΔselAB and ΔfdhF mutants of Clostridioides difficile" (2025). Honors Undergraduate Theses. 431.
https://stars.library.ucf.edu/hut2024/431