Biomineralization and Biosequestration Mechanisms at Lifes Upper Temperatures: A Reappraisal using Novel CryoEM Techniques
EMSL Project ID
40130
Abstract
Given that (i) hyperthermophilic and thermophilic biofilms were some of the earliest microbial communities to inhabit our planet, (ii) such communities evolved and thrived in heavy metal-rich ecosystems, and (iii) new mineral formers are still being discovered in subsurface analog environments like hot springs, it is likely that some members of such communities have inherent toxic element precipitation and sequestration capabilities, yet unrecognized, that evolved to aid in their survival and could ultimately be harnessed for bioremediation purposes. The ability to apply cryoEM techniques recently optimized at EMSL-PNNL and investigate with state-of-the art chemical imaging tools and electron microscopes at EMSL-PNNL and Portland State University are timely in this regard.The primary objectives of this proposal are to (i) confirm recently discovered mechanisms by which hot spring microbes precipitate and sequester mineraloids in hot springs deposits with the use of cryoEM techniques, (ii) survey deployed substratrums used to colonize hyperthermophilic biofilms from hot springs that contain distinctly different concentrations of dissolved metals and reduced gases at hot springs the PI studies in Yellowstone National Park (NPS Permit YELL SCI-01994), and (iii) obtain sufficient data from the techniques and instruments used in this study, should additional taxa be discovered that display evidence either for biomolecule templated minerals/mineraloids or periplasmic-sequestered precipitates, with the intent to publish such results in the open literature. A key aspect of this study is to achieve, by way of a time-point sampling strategy of substratums deployed in different hot springs, a systematic frame-by-frame characterization of the processes involved in the accumulation of high-temperature sinter precipitates. This work builds upon current research by the PI at Portland State University in which hot spring deposits that formed at the same sampling locales as proposed for study here are being investigated to discern how the fidelity of microbial biosignatures entrained in such specimens are altered with subsequent precipitation and taphonomic alteration of the deposits. Though modern biofilms and sinters have been studied extensively with conventional SEM and TEM techniques, a great deal remains to be accomplished in terms of the application of cryoTEM and cryoSEM analysis of such samples. A comparison of the dehydration artifacts obtained during cryoEM and sublimation trials at EMSL-PNNL with the results obtained by others who have used environmental SEM to study hot spring microbial communities suggests that our understanding of biofilm composition and behavior in the environment is in its infancy. Accurate identification of biofilm formation and mineral precipitation/elemental sequestration processes will provide a foundation with which to assess the potential for some key organisms in these biofilms. This will include the development of novel bioremediation strategies, acquisition of data for the development of models of bacterial processes that lead to elemental sequestration, and the capability to decipher how post-depositional processes alter the integrity of a bioremediated deposits.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2010-10-01
End Date
2012-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Cady, S.L. (2011) Biosignatures and Life. Invited Keynote Speaker at the Geobiology in Space Exploration meeting, Marrakech, Morocco <http://irsps.sci.unich.it/education/geoexp2011/program0.php>. Talk with electronically posted abstract.