Use of micromanipulation and "feeder layers" to clone the oyster pathogen Perkinsus marinus

Genetic and biochemical characterization of microbes often requires the use of clonal cultures. A method to clone the oyster parasite Perkinsus marinu s is described. Individual cells are isolated via micromanipulation and mai ntained above an actively proliferating "feeder layer" of P. marinus on a 0 .45-mu m membrane. Extracellular products released from the proliferating f eeder layer can diffuse across the membrane and bathe the isolated cell, st imulating it to proliferate. The method is relatively simple and should be applicable to most protists that can be cultured in the laboratory.