Characterization of the structure of the prokaryotic complex of Antarctic permafrost by molecular genetic techniques

Resumo

A prokaryotic mesophilic organotrophic community responsible for 10% of the total microbial number determined by epifluorescence microscopy was reactivated in the samples of Antarctic permafrost retrieved from the environment favoring long-term preservation of microbial communities (7500 years). No culturable forms were obtained without resuscitation procedures (CFU = 0). Proteobacteria, Actinobacteria, and Firmicutes were the dominant microbial groups in the complex. Initiation of the reactivated microbial complex by addition of chitin (0.1% wt/vol) resulted in an increased share of metabolically active biomass (up to 50%) due to the functional domination of chitinolytics caused by the target resource. Thus, sequential application of resuscitation procedures and initiation of a specific physiological group (in this case, chitinolytics) to a permafrost-preserved microbial community made it possible to reveal a prokaryotic complex capable of reversion of metabolic activity (FISH data), to determine its phylogenetic structure by metagenomic analysis, and to isolate a pure culture of the dominant microorganism with high chitinolytic activity.