Microbial diversity of Late Pleistocene Siberian permafrost samples.

A metagenomic study of the Kolyma lowland permafrost samples, 20-35 thousand years, performed using a Geneclean for Ancient DNA kit (Bio101, United States), revealed 8 phylotypes which belonged to the phyla Actinobacteria and Proteobacteria. Analysis of the 16S rRNA gene clone library showed that most of the clones (48% and 29%) were represented by the genera Arthrobacter and Bradyrhizobium, respectively. For the first time microorganisms of the genera Williamsia, Bradyrhizobium, Filomicrobium and Hansschlegelia were observed in the ancient microbial communities of these ecosystems. Analysis of the isolates 16S rRNA genes revealed the presence of the microorganisms-the representatives of the phyla Firmicutes and Actinobacteria phylogenetically related to known species and being obvious representatives of novel taxa. In situ electron-microscope analysis of total preparations of the studied samples showed the presence of intact bacterial cells of different morphotypes. [ABSTRACT FROM AUTHOR]