Date of Award
5-2026
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Genetics and Biochemistry
Committee Chair/Advisor
Cheryl Ingram-Smith
Committee Member
Kerry Smith
Committee Member
Lesly Temesvari
Abstract
Entamoeba histolytica is a food-and-water-borne human protozoan pathogen that relies on a two-stage life cycle for successful proliferation outside of the host. E. histolytica exists in its dormant cyst form while outside of its host and converts to the motile trophozoite (amoeba) form in the small intestine. The trophozoites colonize the large intestine to cause symptomatic disease in ~10% of infections, resulting in ~100 million cases of amoebic dysentery each year. Trophozoites can convert back to the cyst form, which is shed in feces to continue the infection cycle.
Currently, there is a lack of understanding of the exact molecular mechanism E. histolytica trophozoites use to initiate the encystation process, although glucose limitation appears to play a strong role. Encystation is accompanied by substantial genetic reprogramming in which many genes involved in growth are down-regulated and genes involved in encystation are upregulated. A key event in encystation is formation of the protective chitin cell wall, which consists of chitin and specific proteins.
This thesis examines the role of the chitin synthase genes CHS1 and CHS2, which encode enzymes responsible for chitin synthesis. Expression during early encystation of these two genes as well as genes encoding other chitin cell wall components including the chitin degrading enzyme chitinase and the chitin binding lectins Jessie and Jacob was investigated. The characterization of a CHS1 knockdown strain has also allowed for an examination of its impact on encystation and expression of other encystation factors. In addition, the effect of a chitin synthase inhibitor on encystation was examined. The binding efficiency of this chitin synthase inhibitor to CHS1 and CHS2 was evaluated in silico, and its inhibitory impact on early cyst wall formation was evaluated in vitro using WGA-488 staining and flow cytometry. Lastly, phylogenetic analysis of Entamoeba chitin synthases demonstrated that CHS1 appears to be distinct from other chitin synthase sequences whereas CHS2 is closely related to arthropod and nematode chitin synthases. The findings of this research suggest chitin synthases could prove to be valuable targets for new therapeutics by blocking encystation which would prevent spread of this disease.
Recommended Citation
Talledo, John N., "An Investigation of Entamoeba Histolytica Chitin Synthases and Other Encystation Factors in Early Encystation" (2026). All Theses. 4786.
https://open.clemson.edu/all_theses/4786