Dear Jabir,

Check the article below

Article Diversity, distribution, and expression of diazotroph nifH g...

Hi Jabir

Generally for identification of nitrogen fixers, the gene nifH is used. It encodes the Fe protein of the enzyme nitrogenase so is only found in nitrogen fixers. It also gives a tree very similar to those using 16s. So that might be the best thing to do first: amplify nifH with universal oligos and produce a clone library for sequencing. You can find universal nifH oligo sequences and amplification conditions in the article below (see table 1 for sequences). I've also attached apaper by Moisander et al 2008 which give QPCR primers and probes designed to target different groups (ie different group of cyanobacteria or different types of heterotrophic bacteria. Using QPCR will enable you to quantify what you have in your culture, but you would probably be best sequencing via a clone library first to get a braod handle on what you've got

Sorry - here's the other paper. Also anything by Jon Zehr will be worth your while looking at.

Cheers

Clare

Hi, i am not an expert, but may be you can tale a look for Niclas Engene work on marine benthoc cyanobacteria