Fluorescence autofluorescence

Fluorescence occurs when radiant energy is absorbed and then, almost instantly, some of the energy is re-emitted, usually at a longer wavelength. Primary fluorescence (autofluorescence) occurs in flavo-proteins (13), plant cell wall materials such as lignin (7), and in flagella (14). Secondary fluorescence is when a material binds a fluorescent dye... 

Differences in the spectral properties of various organic substances can also be utilized for diagnostics [10.133]. Natural tissue fluorescence (autofluorescence) has been used for tumour characterization [10.134-136] as well as for caries studies in teeth [10.137,138]. An emerging application is characterization of artheroscleroris in blood vessels [10.139,140]. There are substantial spectral differences in fluorescence spectra from normal and diseased aortic wall, as illustrated in Fig. 10.41, where also the demarcation... 

While fluorescent imaging techniques offer very high sensitivity, there remains the problem of background noise arising from fluorescence from the sample itself (autofluorescence). There are two strategies to overcome this (i) two-photon excitation,32 and (ii) the use of phosphorescent... 

However, engineering of fluorescent marker proteins to determine subcellular protein localizations and associations in planta can be quite challenging since plant cells contain a number of autofluorescent compounds (e.g., lignin, chlorophyll, phenols, etc.,) whose emission spectra interfere with that of the most commonly used green or red fluorophores and their spectral variants... 

For example, lignin fluorescence in roots, vascular tissues, and cell walls of aerial plant parts interferes with imaging at wavelengths between 490 and 620 nm while the chlorophyll autofluorescence in leaves and stems is most problematic between 630 and 770 nm. Thus imaging of GFP and its closest spectral variants such as CFP and YFP is most likely to be problematic in roots, whereas RFPs may be hard to discriminate in chloroplast containing aerial plant tissues [17], These problems have only recently been effectively... 

Raluca Niesner, B. P., Schliische, P. and Gericke, K. H. (2004). Noniterative Biexponential fluorescence lifetime imaging in the investigation of cellular metabolism by means of NAD(P)H autofluorescence. Chem. Phys. Chem. J, 1141-9. 

Schnell, S. A., Staines, W. A. and Wessendorf, M. W. (1999). Reduction of lipofuscin-like autofluorescence in fluorescently labeled tissue. J. Appendix Histochem. Cytochem. 47, 719-30. 

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