Autofluorescence, general

An important feature that influences the performance of the probe to a large extent is the selection of the FRET pair. Generally, fluorophores with high excitation wavelengths are preferred over blue fluorophores in single photon microscopy for applications in tissue since there is no autofluorescence in this region and the ratio... 

We presented the application of this method for the detection and analysis of autofluorescent molecules in living cells. In addition to autofluorescent molecules, fluorescence indicators for Ca2 +, pH, and so on may be unique targets for this method. In general, the fluorescence quantum efficiency of autofluorescence is much lower than that of the fluorescence of the indicators. Therefore, a technique for separating unknown fluorescent components with very different quantum efficiencies is essential. Simultaneous analysis of the spatiotemporal dynamics of autofluorescent molecules and fluorescence indicators would be a powerful approach for revealing complicated responses in living cells. 

Since increased 02 generation appeared to correlate with increased carotenoid biosynthesis, we examined the effect of DQ exposure on carotenoid levels and composition. Exposure of cultures to DQ increased the levels of carotenoid produced by about 40%, and also increased the relative proportion of xanthophylls and diminished the levels of carotene precursors (31). In addition to producing more carotenoids, the increased proportion of xanthophylls would provide greater resistance to oxidative stress since xanthophylls are generally more effective antioxidants than carotenes (2). This pattern of increased levels of carotenoids and a higher proportion of xanthophylls also takes place as cultures age. The astaxanthin pathway may function in part to prevent aging of yeast and possibly to supply antioxidant capacity to their progeny. Microscopic examination of autofluorescence supported that carotenoids are... 

Some special conditions should be noted for fluorescent samples. Glutar-aldehyde is autofluorescent, and so its use should be avoided. If there is no alternative to this fixative, its autofluorescence can be countered by treatment with NaBH. Dyes may be pH sensitive for example, FITC fluorescence yield is significantly reduced if the pH of the mountant is < 8.5-9.0. Some counterstains are autofluorescent (e.g., Feulgen and Nissl stains). Fluorescent latex beads, which can be used as axonal tracers or as implants for the slow release of a variety of soluble factors, are dissolved by alcohol and xylene (see Note 8). In general, background fluorescence increases with time stored. Background can... 

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