Scott O. Rogers

Influenza A virus infects a large proportion of the human population annually, sometimes leading to the deaths of millions. The biotic cycles of infection are well characterized in the literature, including in studies of populations of humans, poultry, swine, and migratory waterfowl. However, there are few studies of abiotic reservoirs for this virus. Here, we report the preservation of influenza A virus genes in ice and water from high-latitude lakes that are visited by large numbers of migratory birds. The lakes are along the migratory flight paths of birds flying into Asia, North America, Europe, and Africa. The data suggest that influenza A virus, deposited as the birds begin their autumn migration, can be preserved in lake ice. As birds return in the spring, the ice melts, releasing the viruses. Therefore, temporal gene flow is facilitated between the viruses shed during the previous year and the viruses newly acquired by birds during winter months spent in the south. Above the Arctic Circle, the cycles of entrapment in the ice and release by melting can be variable in length, because some ice persists for several years, decades, or longer. This type of temporal gene flow might be a feature common to viruses that can survive entrapment in environmental ice and snow.

Ancient Taurus cedar (Cedrus libani A. Rich) wood samples from the Tumulus of King Midas at the Gordion archaeological site (about 2700 years old), near Ankara, Turkey, and from the Al-Aksa Mosque (about 1500 to 1900 years old), Jerusalem, Israel, were characterized by studying the sequences of ribosomal DNA (rDNA) internal transcribed spacers (ITS1 and ITS2). After extraction of the DNA, the ITS regions were amplified utilizing the polymerase chain reaction, followed by sequencing, BLAST searches for similar sequences, and phylogenetic analyses. Fifty-six sequences were obtained. In BLAST searches of existing sequence databases, most were closest to those from humans and fungi. However, two sequences exhibited similarities with conifer ITS sequences. One was an ITS1 region from the Gordion wood specimen, and the other one was an ITS2 region from the Al-Aksa wood specimen. Phylogenetic analyses indicated that both were closest to Taurus cedar (C. libani, also known as Lebanon cedar) ITS sequences from three recent samples of Taurus cedar from two sites in Turkey. However, they exhibited many differences from the recent C. libani rDNA ITS sequences from Turkey, probably due to degradation of the DNA in the ancient samples. The implications of the results on future studies are discussed.

Drilling and laboratory manipulations of glacial ice cores introduce contemporary microbes and biomolecules onto the cores. We report herein a systematic comparative study of several decontamination protocols. Only treatment with 5% sodium hypochlorite eliminated all external contaminating microbes and nucleic acids while maintaining the integrity of those within the cores.