A molecular method to assess bioburden embedded within silicon-based resins used on modern spacecraft materials. Issue 3 (July 2012)

• Record Type: Journal Article
• Authors: Stam, Christina N.; Bruckner, James; Spry, J. Andy; Venkateswaran, Kasthuri; La Duc, Myron T.
• Is Part Of: International journal of astrobiology. Volume 11:Issue 3(2012)
• Page Start: 141
• Page End: 145
• Publication Date: 2012-07
• Subjects: Exobiology -- Periodicals; 576.83905
• DOI: 10.1017/S1473550412000031
• Languages: English
• ISSNs: 1473-5504

Abstract

<abstract abstract-type="normal"> <title>Abstract</title> <p>Current assessments of bioburden embedded in spacecraft materials are based on work performed in the Viking era (1970s), and the ability to culture organisms extracted from such materials. To circumvent the limitations of such approaches, DNA-based techniques were evaluated alongside established culturing techniques to determine the recovery and survival of bacterial spores encapsulated in spacecraft-qualified polymer materials. Varying concentrations of <italic>Bacillus pumilus</italic> SAFR-032 spores were completely embedded in silicone epoxy. An organic dimethylacetamide-based solvent was used to digest the epoxy and spore recovery was evaluated via <italic>gyr</italic>B-targeted qPCR, direct agar plating, most probably number analysis, and microscopy. Although full-strength solvent was shown to inhibit the germination and/or outgrowth of spores, dilution in excess of 100-fold allowed recovery with no significant decrease in cultivability. Similarly, qPCR (quantitative PCR) detection sensitivities as low as ∼10³ CFU ml⁻¹ were achieved upon removal of inhibitory substances associated with the epoxy and/or solvent. These detection and enumeration methods show promise for use in assessing the embedded bioburden of spacecraft hardware.</p> </abstract>