Shift in GFP-spectrum

Posted by Sven Terclavers on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Shift-in-GFP-spectrum-tp590043.html

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Dear list,

 

I have been performing spectral analysis experiments on pig-hearts injected with GFP-transfected stemcells with the Zeiss LSM510 META to define whether GFP was present or not. 1 to 3 days after injection, a spectral curve similar to GFP with a clear peak around 510 nm can be observed, though when scanning hearts 6 weeks after injection (with the same settings of microscope, laser and detectors), I only observe a broader spectral curve with a peak around 540nm, thoug with almost the same intensity.  Since it is very crucial for the project to know whether the stemcells are still present or not after these 6 weeks, I want to make sure that the spectrum I observe is (not) GFP.

 

So the question: is it possible GFP has a spectral shift of about 30nm, and gets a broader spectral curve, due to e.g. change in pH, presence of other proteines or whatever other influences? In addition, if so, is there any good reference available to this phenomenon?

 

Thanks in advance,

 

Sven Terclavers

 

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