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Title: Application of flow cytometry and cell sorting to the bacterial analysis of environmental aerosol samples

item Hernlem, Bradley - Brad
item Ravva, Subbarao

Submitted to: Journal of Environmental Monitoring
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2007
Publication Date: 9/21/2007
Citation: Hernlem, B.J., Ravva, S.V. 2007. Application of flow cytometry and cell sorting to the bacterial analysis of environmental aerosol samples. Journal of Environmental Monitoring. 2007(9) 1317-1322.

Interpretive Summary: Harmful bacteria can be carried from place to place by aerosols on the farm and in the environment. Often it is not possible or not easy to grow these bacteria in the lab although they are able to survive and cause disease. We counted live bacteria in aerosol samples by a method known as flow cytometry. By this method we also sorted and studied particles in aerosol samples according to the way they bent scattered light and then identified the sorted bacteria by DNA analysis. These results show the usefulness of flow cytometry in studying bacteria in aerosols.

Technical Abstract: Flow cytometry (FCM) combined with viability staining is a useful tool in discerning viable bacteria in environmental samples where traditional culture methods may fail. Contamination of aerosol samples with dust and other non-biological particles can interfere with accurate sample analysis and therefore there is a desire to exclude those particles from analysis. Particles were sorted according to their light scattering properties, cultured and isolates obtained. Isolates were cultured in suspension and reanalyzed by flow cytometry. The isolates were also analyzed and identified by DNA sequence analysis. Isolates with statistically similar light scattering properties shared common sequence identification. Isolates exhibited distinct light scattering profiles that roughly correlated with their originating gate, but often the peak of the profile was outside that gate.