Sphingolipids fluorescent

Rasmussen JAM, Hermetter A (2008) Chemical synthesis of fluorescent glycero- and sphingolipids. Prog Lipid Res 47 436-460... 

Use of fluorescent sphingolipid analogs to study lipid transport along the endocytic pathway. Methods 2005 36 186-195. 57. 

The nanosized detection area Ar or volume created by STED also extends the power of fluorescence correlation spectroscopy (FCS) and the detection of molecular diffusion [74,95]. For example, STED microscopy has probed the diffusion and interaction of single lipid molecules on the nanoscale in the membrane of a living cell (Fig. 19.6). The up to 70 times smaller detection areas created by STED (as compared to confocal microscopy) revealed marked differences between the diffusion of sphingo- and phospholipids [74]. While phospholipids exhibited a comparatively free diffusion, sphingolipids showed a transient ( 10 ms) cholesterol-mediated trapping taking place in a < 20-nm diameter area, which disappeared after cholesterol depletion. Hence, in an unperturbed cell putative cholesterol-mediated lipid membrane rafts should be similarly short-lived and smaller. 

Fig. 2. General structural features of fluorescent and spin-labeled lipid analogs. The fluorescent lipids usually contain a short-chain fatty acid, amino-caproic acid, that is derivatized with 4-nitrobenzo-2-oxa-1,3-diazole (NBD), or valeric acid that is derivatized with a boron dipyrromethene difluoride (BODIPY) moiety. For fluorescent phospholipids, X can be hydrogen or the esterified forms of choline, ethanolamine, serine, or inositol. R>r fluorescent sphingolipids, Y can be hydrogen or the esterified fonns of phosphocholine or mono- or oligosaccharides typical of glycosphingolipids. The spin-labeled lipids modified in the fatty acid portion contain a 4-doxylpentanoyl fatty acid in the sn-2 position. Those modified in the polar head group contain a tempocholine moiety in place of choline. The X substituent for the acyl spin-labeled lipids can be hydrogen or the esterified forms of choline, ethanolamine, or serine.

Marks, D.L., Singh, R.D., Choudhury, A., Wheatley, C.L., Pagano, R.E. 2005. Use of fluorescent sphingolipid analogs to study lipid transport along the endocytic pathway. Methods 36 186-195. 

Probes for the Golgi apparatus are fluorescently labeled ceramides and sphingolipids, which tend to associate preferentially with the trans-Golgi. 

An early procedure for sphingosine and sphingolipids used labelling with fluorescamine [215L and another labelling reagent was 2-naphthoxyacetate [216]. More recent procedures used l,6-diphenyl-l,3,5-hexatriene (DPH) for fluorescence enhancement [217,218[ see Figure 11. The mechanism for this is not clear, but seems to involve some kind of intercalation of the DPH within the phospholipid molecules or micelles rather than the formation of true derivatives. 

Lipsky, N. G. Pagano, R. E. Sphingolipid metabolism in cultured fibroblasts microscopic and biochemical studies employing a fluorescent ceramide analogue. Proc. Natl Acad. Set U.S.A 1983, 80, 2608-2612. 

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