Sheila Roitman – PhD dissertation
Expanding the Scope of the Virocell:Viral-Host Interplay in the Marine Environment
Viruses are the most abundant and diverse entities in the marineenvironment, yet little is known regarding the exact nature of the interactionsbetween viruses and their hosts. The virocell concept, a metabolically activecellular host infected with a virus, established a framework for viruses to beconsidered active players in the environment, capable of metabolism andaffecting the entire ecosystem. During my PhD I discovered new ways in whichviruses shape the metabolism of their virocell, that could affectbiogeochemical cycles and the local food chain. Additionally, I isolated andcharacterized a novel virophage, a small virus that infects virocells of a giantvirus and its algae host, first of its kind. This novel algae-virus-virophagesystem enables us to study a rather uncharacterized facet of viruses asparasites of other viruses, and offers us a glimpse into the origin andevolution of viruses infecting eukaryotes. As we continue to shed light on theviral life-styles we understand that the virosphere is a central player in theoceans that should be always accounted for.