در ادامه مطالب پیشین، برای رفع آلودگی یوکاریوتها از محیط کشت سیانوباکترها روشهای زیر پیشنهاد میگردد. مورد نخست از پروفسور ویتون از انگلستان و مورد بعد از پروفسور حمید از پاکستان ارسال شده است.
Getting rid of eukaryotes from cyanobacterial cultures should be simple and routine with cycloheximide. I've done it since the time cycloheximide was sold as actidione (almost forty years ago!). The only problems have been the occasional resistant testate amoeba or ciliate.
Obtaining bacteria-free cultures is of course much more of a challenge, especially those where bacteria are routinely attached to the surface, such as the heterocysts of many Cylindrospermum species. For bacteria it is often best to work with single filaments, preferably hormogonia. In the case of filamentous forms, the majority of species form hormogonia when a period of moderate P-limitation is followed by P enrichment under otherwise favourable conditions (temperature, light etc). Even if bacteria are present in the medium, hormogonia seldom have bacteria firmly attached to the surface.
Individual trichomes can be picked up with very fine glass pipettes (drawn out in a bunsen flame), while using a laminar flow hood, and then taken through a series of four to five washes. It takes a few days practice to get the technique working well. Trichomes from intermittently moist habitats such as rice-fields usually survive well and it should be possible to obtain 70-80% survival rate. Trichomes from permanently wet habitats are more of a challenge, though Arthrospira has proved fairly easy.
Cycloheximide May not be available to all parts of the world, as its supply to some countries is restricted. therefore, serial streaking for the purification of unuicellular and manual picking of filaments under streomicroscope is a good choice.