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Deep UV Native Fluorescence Imaging of Antarctic Cryptoendolithic CommunitiesAn interdisciplinary team at the Jet Propulsion Laboratory Center for Life Detection has embarked on a project to provide in situ chemical and morphological characterization of Antarctic cryptoendolithic microbial communities. We present here in situ deep ultraviolet (UV) native fluorescence and environmental scanning electron microscopy images transiting 8.5 mm into a sandstone sample from the Antarctic Dry Valleys. The deep ultraviolet imaging system employs 224.3, 248.6, and 325 nm lasers to elicit differential fluorescence and resonance Raman responses from biomolecules and minerals. The 224.3 and 248.6 nm lasers elicit a fluorescence response from the aromatic amino and nucleic acids. Excitation at 325 nm may elicit activity from a variety of biomolecules, but is more likely to elicit mineral fluorescence. The resultant fluorescence images provide in situ chemical and morphological maps of microorganisms and the associated organic matrix. Visible broadband reflectance images provide orientation against the mineral background. Environmental scanning electron micrographs provided detailed morphological information. The technique has made possible the construction of detailed fluorescent maps extending from the surface of an Antarctic sandstone sample to a depth of 8.5 mm. The images detect no evidence of microbial life in the superficial 0.2 mm crustal layer. The black lichen component between 0.3 and 0.5 mm deep absorbs all wavelengths of both laser and broadband illumination. Filamentous deep ultraviolet native fluorescent activity dominates in the white layer between 0.6 mm and 5.0 mm from the surface. These filamentous forms are fungi that continue into the red (iron-rich) region of the sample extending from 5.0 to 8.5 mm. Using differential image subtraction techniques it is possible to identify fungal nuclei. The ultraviolet response is markedly attenuated in this region, apparently from the absorption of ultraviolet light by iron-rich particles coating the filaments. Below 8.5 mm the filamentous morphology of the upper layers gives way to punctate 1-2 micron particles evidencing fluorescent activity following excitation at both deep ultraviolet wavelengths.
Document ID
20020002093
Document Type
Conference Paper
Authors
Storrie-Lombardi, M. C. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Douglas, S. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Sun, H. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
McDonald, G. D. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Bhartia, R. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Nealson, K. H. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Hug, W. F. (Photon Systems Covina, CA United States)
Date Acquired
August 20, 2013
Publication Date
April 1, 2001
Publication Information
Publication: General Meeting of the NASA Astrobiology Insititute
Subject Category
Exobiology
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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