Remarkable Diversity of Phototrophic Purple Bacteria in a Permanently Frozen Antarctic Lake

Although anoxygenic photosynthesis is thought to play an important role in the primary productivity of permanently frozen lakes in the Antarctic dry valleys, the bacterial communities responsible for this metabolism remain uncharacterized. Here we report the composition and activity of phototrophic...

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Bibliographic Details
Published in:Applied and Environmental Microbiology
Main Authors: Karr, Elizabeth A., Sattley, W. Matthew, Jung, Deborah O., Madigan, Michael T., Achenbach, Laurie A.
Format: Text
Language:English
Published: American Society for Microbiology 2003
Subjects:
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC169089
http://www.ncbi.nlm.nih.gov/pubmed/12902286
https://doi.org/10.1128/AEM.69.8.4910-4914.2003
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Summary:Although anoxygenic photosynthesis is thought to play an important role in the primary productivity of permanently frozen lakes in the Antarctic dry valleys, the bacterial communities responsible for this metabolism remain uncharacterized. Here we report the composition and activity of phototrophic purple bacteria in Lake Fryxell, Antarctica, as determined by analysis of a photosynthesis-specific gene, pufM. The results revealed an extensive diversity and highly stratified distribution of purple nonsulfur bacteria in Lake Fryxell and showed which phylotypes produced pufM transcripts in situ. Enrichment cultures for purple bacteria yielded two morphotypes, each with a pufM signature identical to signatures detected by environmental screening. The isolates also contained gas vesicles, buoyancy structures previously unknown in purple nonsulfur bacteria, that may be necessary for these organisms to position themselves at specific depths within the nearly freezing water column.