A simple method for plating and cloning ciliates and other protozoa

A simple method is described for plating and cloning ciliates and other protozoa, based on a principle differing from that traditionally used for plating and cloning bacteria and other microorganisms. This procedure, referred to as te silicone-oil-plating-procedure (SOPP), involves vortexing small volumes of culture medium containing protozoa with larger volumes of a non-toxic silicone oil and plating the resulting unstable emulsion in small plastic petri plates. Discrete microdroplets of culture medium form containing protozoa entrapped and immobilized between the hydrophobic surfaces of teh plastic petri dish and the oil. Protozoa, isolated by this method grow, divide, and multiply to form clones. The procedure may be used for plating and cloning protozoa in bacterized and axenic culture. Variations of te basic method may be applied to isolating protozoa from the wild, washing protozoa to remove microorganisms, screening for potential mutants, and for replica plating.