IUBio GIL .. BIOSCI/Bionet News .. Biosequences .. Software .. FTP

Fluorescing E. coli...

KAREN HEATON heatonk at unix.lancs.ac.uk
Wed Mar 3 08:40:48 EST 1999


I have several questions which i would like to put to people in 
various areas of research - please accept my apologies if you receive 
this more than once.


We have transformed E. coli DH5a and HB101 using plasmid 
pUV-BAD to express GFP and found that the cells are not uniform in length. 
 Can someone who has seen either or both of these strains - preferably after 
they have beenstained in some way inform us as to whether they have these
 morphologies if they have not been tinkered with!

When bacteria are DAPI stained some cells look orange under UV light - is 
there a reason for this?


When a protist ingests DTAF stained bacteria, what happens to the 
stain?  Is it and its' fluorescence degraded in the food vacuole or 
does it end up in the medium when it is excreted?

The transformed cells do not fluoresce uniformly -  why is the protein 
 switched on at different rates amongst cells under the same 
conditions?  Is it because of new cells forming - therefore, do you have 
to wait until all cells reach stationary phase before they will all 
fluoresce at their maximum?

Will all the cells eventually fluoresce?  Is it possible that some of the 
cells will be non-fluorescing or is this impossible 
since the plasmid gives ampilillin resistance and they have grown on 
plates containing ampicillin.

All suggestions gratefully received...


More information about the Protista mailing list

Send comments to us at archive@iubioarchive.bio.net