title: Real-time analysis of metabolic activity within Lactobacillus acidophilus by phasor fluorescence lifetime imaging microscopy of NADH.
abstract: Nicotinamide adenine dinucleotide (NADH) is an endogenous fluorescent molecule commonly used as a metabolic biomarker. Fluorescence lifetime imaging microscopy (FLIM) is a method in which the fluorescence decay is measured at each pixel of an image. While the fluorescence spectrum of free and protein-bound NADH is very similar, free and protein-bound NADH display very different decay profiles. Therefore, FLIM can provide a way to distinguish free/bound NADH at the level of single bacteria within biological samples. The phasor technique is a graphical method to analyse the entire image and to produce a histogram of pixels with different decay profile. In this study, NADH fluorescence decay profiles within Lactobacillus acidophilus samples treated using different protocols indicated discernible variations. Clear distinctions between fluorescence decay profiles of NADH in samples of artificially heightened metabolic activity in comparison to those of samples lacking an accessible carbon source were obtained.
authors.affiliation: School of Science and Health, University of Western Sydney, Richmond, NSW, Australia.
authors.forename: Keenan
authors.initials: K
authors.lastname: Torno
authors.forename: Belinda K
authors.initials: BK
authors.lastname: Wright
authors.forename: Mark R
authors.initials: MR
authors.lastname: Jones
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Digman
authors.forename: Enrico
authors.initials: E
authors.lastname: Gratton
authors.forename: Michael
authors.initials: M
authors.lastname: Phillips
mesh_terms: D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007779:Lactobacillus acidophilus / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods*; D009243:NAD / Q000032:analysis*; D011485:Protein Binding; D013997:Time Factors
chemical_list: D009243:NAD