This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Soil is the major environmental reservoir of fungi that cause human diseases. Surveys of medically important fungi have been carried out using selective isolation approaches, but, to our knowledge, comprehensive molecular surveys of fungal diversity in soil have yet to be applied to surveillance in medical mycology. The Taylor lab has spearheaded extensive soil sampling combined with in-depth sequencing of PCR clone libraries in order to characterize fungal diversity in Interior Alaska. To date, we have generated roughly 100,000 fungal ITS clone sequences, a number surpassing the total number of fungal ITS sequences in GenBank. Here, we propose a pilot study to investigate the diversity of fungi of concern to human health recovered from these soil PCR libraries. We will carry out comprehensive phylogenetic analyses of all fungi of medical interest in our massive sequence database. As exemplars, we present here phylogenetic analyses of the genus Cryptococcus, a leading causative agent of respiratory diseases and meningitis in immune-compromised individuals, and the genus Candida, species of which belong to the normal human flora, but which occasionally cause dangerous systemic infections. Sequences recovered from Alaskan soils in both fungal groups are diverse, and include putative new species with no prior known sequences. We also propose to amplify and sequence additional loci in cases where the relationship of Alaskan entities to known clinical strains is uncertain based solely on ITS sequences. Our ultimate goal is to obtain additional external funding to expand this surveillance work through application of an Affymetrix microarray that is under development and through sampling of soils in additional regions of Alaska, particularly the southeast where monitoring for the outbreak pathogen Cryptococcus gattii would seem warranted.
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