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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOPHOTONICS - THE APPLICATION OF NOVEL IMAGING METHODOLOGIES TO LIVESTOCK PRODUCTION RESEARCH

Location: Warmwater Aquaculture Research Unit

Title: Photonic Plasmid Stability of Transformed Salmonella Typhimurium: A Comparison of Three Unique Plasmids

Authors
item Moulton, K -
item Ryan, P -
item Lay, Jr, Donald
item Willarad, S -

Submitted to: BMC Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 27, 2009
Publication Date: July 27, 2009
Citation: Moulton, K., Ryan, P., Lay Jr, D.C., Willarad, S. 2009. Photonic Plasmid Stability of Transformed Salmonella Typhimurium: A Comparison of Three Unique Plasmids. BMC Microbiology. 9:152-159.

Interpretive Summary: Acquiring a highly stable light-emitting plasmid in transformed Salmonella typhimurium for use in studies of bacterial tracking in living systems is critical to research model development. The objective of this study was to determine stability of transformed Salmonella Typhimurium (S. typh-lux) using three different plasmids and characterize their respective photonic properties in the presence and absence of selective antibiotic pressure in the laboratory. In addition, our data determined the respective photonic properties (luminescent:bacterial concentration correlations and minimum and maximum luminescent thresholds) of each plasmid using different imaging platforms and by varying concentrations of S. typh-lux bacteria. In summary, these data characterize photon (light-emitting) stability properties for S. typh-lux transformed with three different photon generating plasmids that may facilitate real-time Salmonella tracking using in vivo or in situ biophotonic paradigms.

Technical Abstract: Background: Acquiring a highly stable photonic plasmid in transformed Salmonella Typhimurium for use in biophotonic studies of bacterial tracking in vivo is critical to experimental paradigm development. The objective of this study was to determine stability of transformed Salmonella Typhimurium (S. typh-lux) using three different plasmids and characterize their respective photonic properties. Results: In presence of ampicillin (AMP), S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 plasmids exhibited 100% photon-emitting colonies over a 10-d study period. Photon emitters of S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 without AMP selection decreased over time (P < 0.05), representing only 11 ± 1%, 35 ± 1% and 43 ± 1%, respectively, of original photon emitting properties of the bacterial population by d 10. Photonic emissions were positively correlated with bacterial concentration (P < 0.05) for pAK1-lux, pCGLS-1 and pXEN-1 (r = 0.96, 0.98 and 0.82, respectively). When stratified by high, medium and low density bacteria concentrations, photonic emissions for high density populations containing pAK1-lux, pCGLS-1 and pXEN-1 resulted in differences of photonic emissions across a range of bacterial concentrations (1 × 107 to 1 × 109 CFU, P < 0.05) with positive correlations (P < 0.05) of (r = 0.72, 0.46 and 0.72, respectively). The correlation of photonic emissions with bacterial concentrations for samples with medium and low density bacteria (pAK1-lux, pCGLS-1, and pXEN-1 plasmids) imaged in tubes were also positively correlated (medium; r = 0.69, 0.49, 0.46, low; r = 0.90, 0.71, 0.68, respectively; P > 0.05); although photonic emissions across a range of bacterial concentrations were not different (1 × 104 to 1 × 106 CFU, P > 0.05). For very low density bacterial concentrations imaged in 96 well plates photonic emissions were positively correlated with bacterial concentration (P < 0.05) for pAK1-lux, pCGLS-1, and pXEN-1 plasmids (r = 0.99, 0.99, and 0.96, respectively), and photonic emissions across a range of bacterial concentrations (1 × 103 to 1 × 105 CFU) low to high were different in the 96-well plate format (P < 0.05). Conclusion: These data characterize photon stability properties for S. typh-lux transformed with three different photon generating plasmids that may facilitate real-time Salmonella tracking using in vivo or in situ biophotonic paradigms.

Last Modified: 8/27/2014
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