Is it possible for cyanobacteria to use nitrate (from culture media) and convert it into urea (exogenous) to be detected by urea assay?
I cannot see they would have any benefit of such a process. Urea assays interact with different compounds, so perhaps you could describe the analytical principle you used.
Hello Thanks for the reply.
our culture fed on nitrate as the nitrogen source gave signals for presence of (residual) urea (spectrophotometric urea assay) in culture media. Can cyanobacteria assimilate nitrate to release exogenous urea in culture?
Neha - if the cyanobacteria convert the nitrate to urea the urea is not exogenous (exogenous means it originates from 'outside' the organisms). It could be considered endogenous to the cyanobacteria, but this term is not useful in the context of your question. I am also not sure that cyanobacteria would make urea, they should be making amino acids instead of breaking them down. Is there a contaminating organism in your culture media?
Dear Dr. Wolff. First of all thanks for the response.
We are seeing signals for urea on the culture fed with nitrate. Its highly unlikely for cyanobacteria to convert nitrate to urea and relase it from the cell. Could there be a reason for the same. As you mentioned cyanobacteria might be making some amino acid. Could please elaborate on that and also guide how can that be tested?
Our culture is axenic and there is no contamination.
I am not an expert in this area so hopefully someone with knowledge will jump in to help. I can only guess, but I think the urea signal might be from a similar compound that the bacteria are making as a byproduct/waste or if they are being negatively affected by a toxin or lack of a nutrient they may being producing some waste materials. Also, make sure the axenic culture really does not have some other organism (or virus) present, as these may not be culturable but can be present (even attached to the cyanobacteria) as they were transferred into the culture.
Please describe the method of urea analysis. Just stating that it is a colorimetric is not an answer, as there are many colorimetric assays based on different chemical reactions. Several are very unspecific!
Poster Comparison of analytical options for urea in pool water
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