Author ORCID Identifier:

https://orcid.org/0000-0002-7348-1015

Date of Graduation

8-2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Biology (PhD)

Degree Level

Graduate

Department

Biological Sciences

Advisor/Mentor

Kral, Timothy

Committee Member

Fan, Chenguang

Second Committee Member

Moradi, Mahmoud

Third Committee Member

Evans White, Michelle

Keywords

Halo Assay- SSV titer quantification; Heat Shock Proteins; qPCR for titer quantification; Relative expression of HSP; Sulfolobales; Sulfolobus Spindle Shaped Virus

Abstract

The Sulfolobus Spindle-shaped virus (SSV) is among the most studied archaeal viruses, particularly in extreme environments. This virus predominantly infects multiple Crenarchaea from the Sulfolobaceae family. These hosts thrive in extreme environmental conditions, such as sulfuric hot springs, with a pH of 2 to 4 and a temperature of 76-80˚C. Sulfolobales exhibit a wide geographical distribution across volcanic hot springs. The Sulfolobus Spindle-shaped Virus (SSV), encompassing strains such as SSV1 and SSV8, employs a non-lytic replication strategy in hosts belonging to the order Sulfolobales. The SSV-Sulfolobales system can be cultured in liquid and gellan gum solid media. A comprehensive study has been performed to determine the host range of a specific SSV type and identify the hosts susceptible to SSV infection. This study examines the multiple methods used in SSV titering and the impact of each virus particle count technique on the interactions between single viruses and single hosts (SVSH) across multiple sympatric and allopatric host-virus pairs. This involves conducting proteomic analysis, such as the regulation of heat shock proteins (HSP) of the host after each round of SVSH infection. This study focuses on two viruses: a low-virulence strain (SSV1) and a highly virulent strain (SSV8), which infect hosts of the Sulfolobales from various biogeographic regions. SSV infection in Sulfolobales hosts resulted in growth inhibition; hence, SSV infection may potentially serve as an environmental stressor on hosts and regulate Archaeal group II chaperonins (also known as Heat Shock Proteins). This study focuses on the transcriptomic and proteomic regulation of Heat Shock Proteins in the S. solfataricus P2 strain infected with SSVs (e.g., SSV1 and SSV8). It compares the outcomes with those of uninfected controls to explore whether viral infection induces sufficient stress to upregulate Heat Shock Proteins (HSPs). This dissertation elucidates how variations in elemental mass influence elemental stoichiometry, which, in turn, can either promote host growth or facilitate virus propagation by using the SVSH on S. islandicus (both natural and cured strain) infected with SSV1 and SSV8. This pivotal research will explore previously uncharted territories and a positive correlation between relative virulence and elemental stoichiometry in stably SSV-infected Sulfolobales. One of the future aspects of this study will be to complement the genomic and transcriptomic analysis of both the host and the virus, which may contribute to providing a definitive understanding of their differential interactions. Key Words: Sulfolobales, Sulfolobus Spindle-shaped Virus (SSV), Crenarchaea, SVSH, heat shock proteins, infection dynamics, relative virulence.

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