Detection and characterization of ancient fungi entrapped in glacial ice

Glacial ice is a unique matrix that is capable of protecting microorganisms for long-term preservation. The organisms entrapped in glacial ice can pro vide information on evolutionary processes and ancient biodiversity. The ma jor objective of this study was to detect and characterize ancient fungi in glacial ice and determine their liability. We developed a protocol using r igorous decontamination procedures, conventional cultural methods, and mole cular techniques (polymerase chain reaction amplification of fungal ribosom al DNA internal transcribed spacers, followed by sequence analyses) to exam ine the ancient fungi entrapped in glacial ice. Fifteen glacial ice subcore s, ranging in age from several hundred to 140 000 yr, from two locations in Greenland were used in this study. One hundred ninety fungal isolates were obtained using conventional cultural methods. In this paper ive report the morphological and molecular characteristics of eight isolates, including t wo Pencillium spp, three Cladosporium spp., one Ulocladium sp., one basidio mycete (Pleurotus sp.), and one unknown ascomycete. In addition, ten fun ga l sequences were amplified and sequenced directly from ice meltwater. One o f them was identified as a basidiomycete. The other nine were classified as ascomycetes, of which three sequences had very low similarities with conte mporary sequences in Gen-Bank. The results from this study may facilitate t he future use of ancient fungi in studies of fungal ecology, distribution, epidemiology, phylogeny, and evolution.