Low-temperature recovery strategies for the isolation of bacteria from ancient permafrost sediments

Springer Science and Business Media LLC - Tập 4 - Trang 165-173 - 2000
Tatiana Vishnivetskaya1, Sophia Kathariou1, John McGrath1, David Gilichinsky2, J. M. Tiedje1
1Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA Fax: 1-517-353-2917 e-mail: [email protected], , US
2Laboratory of Soil Cryology, Institute for Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow, Russia, , RU

Tóm tắt

Permafrost represents a unique ecosystem that has allowed the prolonged survival of certain bacterial lineages at subzero temperatures. To better understand the permafrost microbial community, it is important to identify isolation protocols that optimize the recovery of genetically diverse bacterial lineages. We have investigated the impact of different low-temperature isolation protocols on recovery of aerobic bacteria from northeast Siberian permafrost of variable geologic origin and frozen for 5000 to 3 million years. Low-nutrient media enhanced the quantitative recovery of bacteria, whereas the isolation of diverse morphotypes was maximized on rich media. Cold enrichments done directly in natural, undisturbed permafrost led not only to recovery of increased numbers of bacteria but also to isolation of genotypes not recovered by means of liquid low-temperature enrichments. On the other hand, direct plating and growth at 4°C also led to recovery of diverse genotypes, some of which were not recovered following enrichment. Strains recovered from different permafrost samples were predominantly oligotrophic and non-spore-forming but were otherwise variable from each other in terms of a number of bacteriological characteristics. Our data suggest that a combination of isolation protocols from different permafrost samples should be used to establish a culture-based survey of the different bacterial lineages in permafrost.