GFP in low oxygen tension?

PAULH at srv0.bio.ed.ac.uk PAULH at srv0.bio.ed.ac.uk
Tue Nov 21 14:13:34 EST 1995

Dear subscribers,

I have recently attempted to introduce GFP gene (from clone pGFP10.1 from 
Prasher, no induced mutations) into the malarial parasite Plasmodium 
falciparum during its asexual stage (the parasite is in red blood cells). No 
fluorescence was ever observed although many experimental conditions were 
attempted. Given that there may be many reasons why the protein is not 
expressed, or even functional should it be expressed, I am interested in 
exploring the possibility that a low oxygen tension would be responsible. 

Plasmodia in asexual culture are usually kept in 3% oxygen, although several 
clonal lines may be cultured in up to 15-17%. The haemoglobin in the 
erythocyte would also be envisaged to "mop up" what oxygen is available. There 
are suggestions that although Plasmodia are micro aerophiles they may 
actually be faculative anaerobes. They only use their electron transport system 
for pyrimidine biosynthesis, not for generating energy, they take ATP from 
the erythrocyte (or at least thought to!).

I would ask if anyone has an opinion regarding the possibility that" Plasmodia 
find it hard to express a functional GFP as oxygen is lacking?" Is there any idea 
of the affinity of GFP for oxygen? Are mutants available for low oxygen 
conditions to test this idea?

I would appreciate any comments to the email address below as I am not sure 
that I am a subscriber to this network as I have recieved no messages since 



Paul Horrocks
Institute of Cell and Molecular Biology
University of Edinburgh
Edinburgh EH9 3JR
Scotland, UK.

Email paulh at bio.srv0.ed.ac.uk
Tel.  (+44) 131 650 5395
Fax. (+44) 131 668 3870
Email from Paul Horrocks, ICMB, U.o. Edinburgh
paulh at srv0.bio.ed.ac.uk

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