tetrqacylin and GFP in Pseudomonas sp. (fwd)

[Deena Errampalli]

Dear fluoronetters,
 
In our lab, we have transformed Pseudomonas sp. with green fluorescent 
protein (gfp) and the tetracyclin was the antibiotic marker. Southern 
hybridizations indicated that  the transformants do contain gfp. When I 
checked the transformants for the stability of the gfp insert, 
I have noticed that the transformants fluoresced only on the medium with 
tetracycline but not on the medium without tetracycline. I transferred 
the non-fluorescing colonies from the medium without tetracyclin to fresh 
medium with and without tetracyline. Again, I found that the colonies on 
tetracyclin fluoresced while the clonies on the medium without 
tetracyclin did not fluoresce.

Here are my questions, 
1. Did any one of you notice similar tetracyclin related problems?
2. Does the tetracyclin itself cause the bacteria to fluoresce?

Comments/suggestions on the fluorescence nature of the
tetracyclin (that is used as an antibiotic marker) are welcome.

Deena
Deena Errampalli, Ph.D.
Dept. of Environmenatal Biology
University of Guelph
Guelph, Ontaro, N1G 2W1, Canada.