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Phylogenetic and physiological diversity of microorganisms isolated from a deep greenland glacier ice coreWe studied a sample from the GISP 2 (Greenland Ice Sheet Project) ice core to determine the diversity and survival of microorganisms trapped in the ice at least 120,000 years ago. Previously, we examined the phylogenetic relationships among 16S ribosomal DNA (rDNA) sequences in a clone library obtained by PCR amplification from genomic DNA extracted from anaerobic enrichments. Here we report the isolation of nearly 800 aerobic organisms that were grouped by morphology and amplified rDNA restriction analysis patterns to select isolates for further study. The phylogenetic analyses of 56 representative rDNA sequences showed that the isolates belonged to four major phylogenetic groups: the high-G+C gram-positives, low-G+C gram-positives, Proteobacteria, and the Cytophaga-Flavobacterium-Bacteroides group. The most abundant and diverse isolates were within the high-G+C gram-positive cluster that had not been represented in the clone library. The Jukes-Cantor evolutionary distance matrix results suggested that at least 7 isolates represent new species within characterized genera and that 49 are different strains of known species. The isolates were further categorized based on the isolation conditions, temperature range for growth, enzyme activity, antibiotic resistance, presence of plasmids, and strain-specific genomic variations. A significant observation with implications for the development of novel and more effective cultivation methods was that preliminary incubation in anaerobic and aerobic liquid prior to plating on agar media greatly increased the recovery of CFU from the ice core sample.
Document ID
20040092777
Document Type
Reprint (Version printed in journal)
Authors
Miteva, V. I. (NASA Headquarters Washington, DC United States)
Sheridan, P. P.
Brenchley, J. E.
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Publication Information
Publication: Applied and environmental microbiology
Volume: 70
Issue: 1
ISSN: 0099-2240
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other