Date of Award

2026

Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy in Biochemistry and Molecular Biology (PhD)

Administrative Home Department

Department of Chemistry

Advisor 1

Tarun K. Dam

Committee Member 1

Stephen Techtmann

Committee Member 2

Mark Tang

Committee Member 3

Patricia Heiden

Abstract

Plants synthesize a variety of bioactive compounds and proteins that make important contributions to biomedical research. This dissertation describes a new protein (Hylin) and a new bioactive compound (CALI) from two different plant species. Hylin was purified by “Capture and Release” (CaRe) method and affinity chromatography. Subunit and native molecular weight of the lectin were determined by SDS-PAGE and gel filtration chromatography, respectively. Binding specificity of Hylin was analyzed by hemagglutination inhibition assays and spectrophotometry. Hylin agglutinated rabbit red blood cells (RBC) but not human RBC. Ligand binding studies revealed high affinity interactions of Hylin with specific glycan epitopes that are analogous to certain surface antigen structures of cancer cells, RNA viruses and yeast. Therefore, we hypothesized that Hylin was likely to have antiviral, anticancer and antifungal effects. We tested the hypothesis and found the following: (1) Hylin showed anti-HIV activities, as determined by using MT-4 cells and four strains of HIV (HIV-1 NL4.3, HIV-1 HE, HIV-1 IIIB and HIV-2 ROD). (2) Hylin caused significant morphological deformation of triple-negative breast cancer cells (MDA-MB-231). (3) When treated with Hylin, ripples appeared on fungal (yeast) cell wall, indicating strong antifungal stress caused by Hylin.  In addition, Hylin was able to identify a pathological marker in human blood plasma. Such useful properties of Hylin make it a potentially versatile tool for clinical research. The second part of the dissertation focuses on CALI, which is a new bioactive plant compound that belongs to a group of intriguing natural products discovered in our lab. Members of this group have a specific way of cell killing. They dock on the cell surface, form pores through the cell membranes and then completely disintegrate the cells. CALI was purified by size exclusion chromatography and HPLC. Fractions were analyzed by MALDI-TOF MS and ESI. Structural analysis and colorimetric assays suggest that CALI has a lipid core which is covalently linked to sugar chains. The cell killing ability of CALI makes it a promising antifungal and anticancer compound. Taking together, this dissertation describes two new plant products that have the potential to be used in clinical research.

Available for download on Thursday, April 29, 2027

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