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Investigation of mycogenic elemental selenium nanoparticles produced by Se(IV/VI)-reducing fungi under anoxic conditions


EMSL Project ID
50528

Abstract

Selenium (Se) is both a micronutrient required for most life and an element of environmental concern due to its toxicity at high concentrations. Selenium can exist as volatile, aqueous, or insoluble Se(-II), sparingly soluble Se(0), or aqueous Se(IV or VI) compounds in the environments. While most knowledge of biotic Se transformations is related to bacterial processes, recently, common soil fungi have been shown to perform Se (IV/VI) oxyanion reduction under oxic and anoxic conditions, forming both solid nanoparticulate Se(0) and volatile Se(-II) phases. As a result, this influences the concentration, distribution, and bioavailability of Se in water and soil environments. However, little is understood about the chemical or genetic mechanism(s) of this transformation over time. To this end, culture experiments of Alternaria alternata and Paraconiothyrium sporulosum will be grown with 0.1 mM selenite (Se(IV)) to characterize the geochemical and genomic responses to elevated Se concentrations and elucidate the mechanism(s) of mycogenic Se transformations under anoxic conditions. With high resolution electron microscopy technology available at EMSL, information about the quantity, location, size, stability, and crystallinity of mycogenic Se nanoparticles through time will be obtained. As part of a larger project, we will quantify the amount of biomass-associated Se, track the amount of Se remaining in solution, and discern the location and speciation of Se with respect to the fungal cells while simultaneously monitoring the genes active during Se reduction over 60 days. By comprehensively examining Se transformations in these fungi from a combined geochemical and genomic approach including a gene regulatory model, more accurate predictions for the cycling, transformation, and transport of Se in natural and contaminated environments will be achieved.

Project Details

Project type
Exploratory Research
Start Date
2018-10-21
End Date
2019-09-30
Status
Closed

Team

Principal Investigator

Cara Santelli
Institution
University of Minnesota

Team Members

Mary Sabuda
Institution
University of Minnesota