Viruses from extreme thermal environments

Viruses of extreme thermophiles are of great interest because they serve as model systems for understanding the biochemistry and molecular biology req uired for life at high temperatures. In this work, we report the discovery, isolation, and preliminary characterization of viruses and virus-like part icles from extreme thermal acidic environments (70-92 degreesC, pH 1.0-4.5) found in Yellowstone National Park. Six unique particle morphologies were found in Sulfolobus enrichment cultures. Three of the particle morphologies are similar to viruses previously isolated from Sulfolobus species from Ic eland and/or Japan. Sequence analysis of their viral genomes suggests that they are related to the Icelandic and Japanese isolates. In addition, three virus particle morphologies that had not been previously observed from the rmal environments were found. These viruses appear to be completely novel i n nature.