Hartmandia sp. (acanthamoeba) as a Tissue Culture Contaminant

Summary

An occasional tissue culture contaminant, Hartmanella sp. (acanthamoeba), can be confused with tissue cells or viruses. Its similarities to tissue cells and macrophages have been recorded by cinematography. It was found to destroy tissue-cultured cells by proceeding rapidly around them until the cultured cells rounded up and were then pulled out of the field by the amebas. The relationship of the trophozoite form to the encysted form was found to vary in a reciprocal and cyclical fashion. Under adverse conditions, such as cold or lack of medium change, the cystic form predominated, whereas the trophozoite form was more numerous under good conditions. The emergence of the active trophozoite form from the cyst, leaving the empty shell behind, was recorded cinematographically. The film showing these events is available from the film library of the Tissue Culture Association.