For testing several FISH probes it would be very useful to work with cultures of these organisms (especially for Nitrosococcus and wb1-A12). It would be best to get these cultures from Europe, and even better if they were actively growing.
The problem auf the nitrifier culture is that they normally not storied in instititions like the DSMZ, because the growing after freezing often not works. So you need active growing cultures.
The microbiology of the University of Hamburg have a unique "Stammsammlung" of nitrifiers. Please ask Andreas Pommerening for the Ammonia oxidizers or Eva Spieck for Nitrite oxidizers.