Searching for Megaviruses in Iceland

Schimmel/Conrades Science Center Atrium

The proposed Megavirales order comprises members of the previously known nucleocytoplasmic large DNA viruses (NCLDVs). Virus families in the Megavirales order include Poxviridae, Ascoviridae, and the recently explored families of megaviruses infecting free living amoeba such as Mimiviridae, Marseilleviridae, and Pandoraviridae. Megaviruses have been isolated from water and soil samples from Chile, France, India, and the United States. We chose to study the occurrence of megaviruses in Iceland because of the diverse habitats all within one island. No research has been carried out on the presence of megaviruses in Iceland. Samples of water and soil were collected from lava fields, moss/lichen mountain fields and mixed forestry plantations. Acanthamoeba castellanii (ATCC #30010) at a 5x105 cells/ml concentration was used in an amoebal co-culture. A 1:10 dilution of soil or water sample preparation was added to each well. Cell confluence estimates were taken immediately after inoculation and plates were incubated at 28⁰C. After 72 hours, wells containing mixed forestry plantation soil saw 48% lysis, followed by 44% lysis in wells containing lava field soil, and 59% lysis in wells containing moss/lichen mountain field soil. The co-cultures were subcultured onto A. castellanii plus antibiotics at a 1:10 dilution. Percent lysis for wells containing mixed forestry plantation soil, lava field soil, and moss/lichen mountain field soil was 19%, 22%, and 31% respectively. These data suggest A. castellanii may be infected with viruses, potentially megaviruses, originating from the various samples.