Our research is focused on the isolation and characterization of viruses from high temperature (>80 °C) acidic (pH<3.0) environments found in Yellowstone and other thermal sites worldwide.
The long term goal of this research is to identify and to characterize the unusual viruses replicating in these environments and to use them as basic tools for elucidating unique biochemical adaptations required for life at high temperatures.
Major findings to date include the isolation of many novel archaeal viruses that are unlike previously described viruses. The combined genetic, biochemical, and structural analysis of these viruses reveal features unique to archaeal viruses.
To date, we only have a limited knowledge of viruses that replicate in Archaea as compared to viruses of Bacteria and Eucarya and the role these viruses play in the environment. The central focus of our research is the isolation, detailed molecular characterization, and phylogenic analysis of new archaeal viruses from high temperature (>80 °C) acidic (pH<3.0) environments found in YNP and other thermal features worldwide. In addition, we are interested in how archaeal virus populations respond to changes in the geochemistry of a particular Yellowstone thermal feature. The overall rationale for these studies is that an understanding of these viruses will dramatically expand our knowledge of archaeal virus diversity, provide new biochemical insight into adaptations required for life at high temperatures, and contribute to our understanding of the role viruses played in evolution.
Isolation and molecular characterization of novel viruses from high temperature acidic environments
Over the past few years, we have developed techniques for the isolation, purification, molecular characterization, and structural analysis of viruses from Yellowstone’s acidic thermal features. To date, we have discovered 13 novel viruses and virus-like particles. These viruses all replicate in hyperthermophilic hosts belonging to the Crenarchaeota kingdom of Archaea. Each virus type has a morphology and genetic component completely unrelated to other known viruses. Sequence analysis of several of the viral genomes reveals that their encoded genes share little or no similarity to genes in the public data bases. However, structural analysis of one virus shows a common architecture that is also shared by viruses of Bacteria and Eucarya. This is the first identification of a virus architecture that spans all three domains of life and suggests that this architecture existed before the separation of each domain.
Monitoring changes in viral populations within Yellowstone acidic thermal features
Three long-term monitoring sites have been established to monitor changes in viral populations over time. Each site shares the characteristics of being a high temperature (>80 °C), acidic (pH<3.0) hot spring. However, the age of each hot spring and the water geochemistry of each site are quite different. For the past year we have been directly monitoring every 30 days both the changes in water geochemistry and viral populations. To our surprise, we have seen dramatic shifts in both the water geochemistry and the viral populations. In addition, we have completed the sequencing and phylogenetic analysis of one virus type from acidic hot springs in Yellowstone, Japan, Russia and Iceland.