Spore Disruption Analysis and Detection Limit Determination at Low Volume Amplifications (2-10 uL) of Bacillus globigii Using eTags
In the post 9/11 world the threat of bioterrorism attacks in public venues has ignited a demand to develop a cost effective autonomous pathogen detection system capable of detecting the multitude of biological agents that can pose a threat to public safety. The major cost of such a pathogen detection system is the large volume of reagents it must expend. With the goal of reducing the reagent consumption, and therefore cost, of a pathogen detection system, we used the spore-forming bacteria Bacillus globigii (Bg) as a surrogate for the pathogen Bacillus anthracis (anthrax) to determine the lowest amplifiable volume and lowest concentration of amplified sonicated and unsonicated Bg spores that would still be detectable using capillary electrophoresis. We created a serial dilution of unsonicated Bg spores ranging in concentration from 10{sup 8} to 10{sup 1} cfu/mL. From each of these unsonicated spore dilutions we formed three aliquots that were sonicated to disrupt the spores. These sonicated aliquots were analyzed alongside the unsonicated spore samples for each dilution at reaction volumes of 25, 10, and 2 {micro}L. All samples were amplified through a polymerase chain reaction (PCR) in the presence of small fluorescent molecules known as electrophoretic tags (eTags), which were analyzed with capillary electrophoresis to detect the presence of certain nucleic acid signatures. Using this process, Bg samples with concentrations as low as 10{sup 1} cfu/mL and total reaction volumes of amplification as small as 2 mL were readily detectable. Interestingly, detection was more consistent for Bg samples with initial spore concentrations between 10{sup 6} and 10{sup 3} cfu/mL, with the higher and lower concentrations yielding less compelling results. The volume of the sample also affected the efficacy of detection, with detection for 2 {micro}L samples compromised in relation to 25 and 10 {micro}L samples. Detection of sonicated Bg spores appeared to be just as efficient and reliable as detection of unsonicated Bg spores. This work is a small portion of a much larger project being researched at LLNL and Sandia National Laboratory to develop a low cost briefcase size autonomous detector for small-scale 24/7 detection of a variety of common biothreat agents.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 919212
- Report Number(s):
- UCRL-TR-214385; TRN: US200825%%221
- Country of Publication:
- United States
- Language:
- English
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