IMR Press / FBL / Volume 10 / Issue 2 / DOI: 10.2741/1648

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
Autofluorescence as a viability marker for detection of bacterial spores
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1 Centre de recherche, Hôpital Laval, Institut Universitaire de cardiologie et de pneumologie de l'Université Laval, Québec, Canada
2 Biological detection group, Defence R & D Canada Suffield, CFB Suffield, Ralston, Alberta, Canada
3 Département de biochimie et microbiologie, Faculté des sciences et de génie, Université Laval, Québec, Québec, Canada
Front. Biosci. (Landmark Ed) 2005, 10(2), 1647–1653; https://doi.org/10.2741/1648
Published: 1 May 2005
Abstract

Recent biological terrorism events have indicated that bacterial spores such as Bacillus anthracis are real threat agents. Real time detection of biological agents is possible with the use of an ultraviolet Fluorescent Aerodynamic Particle Sizer (FLAPS) that measures particles' intrinsic fluorescence. It is important to know whether intrinsic fluorescence could be used to estimate agents' viability. Two categories of Bacillus spore populations can be differentiated by the intensity of intrinsic fluorescence emitted by ultraviolet (UV) stimulation : autofluorescent and non-autofluorescent. This study was performed to determine whether intensity of autofluorescence correlates with spore viability. Spores were analyzed using flow cytometer (equipped with a cell sorter) to mimic optical properties of FLAPS. Autofluorescent and non-autofluorescent spores were sorted according to the intensity of autofluorescence emitted following UV stimulation. Culturability, membrane integrity, membrane potential and dipicolinic acid (DPA) content were assessed. Autofluorescent spores were 1.7 times more culturable than the corresponding non-autofluorescent population. Moreover, a small proportion of autofluorescent spores exhibited extracellular membrane damages. Autofluorescent spores also showed higher membrane potential activity and contained higher levels of DPA. In conclusion, this study documents that the overall viability potential of bacterial spores can be assessed by UV flow cytometry used in the FLAPS technology.

Keywords
Flow cytometry sorting
Ultraviolet laser
Intrinsic fluorescence
Bacillus anthracis
Biological terrorism
Real-time detection
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