Withdrawal of the Concept of the Occurrence of Classical Mitosis in Bacteria

Abstract

I WISH to retract the concept previously presented by me¹, and to which I have been committed, that classical mitosis occurs in bacteria. This interpretation of cytological material was developed on the basis of routine microscopy on stained preparations. The configurations observed were interpreted using instrumentation of inadequate resolution to solve the problem of the mechanism of division of this group of organisms. It seems likely that this interpretation of structures by white-light microscopy does in fact depend on the presence of not only nuclear material which can assume a multiplicity of forms, but also on the presence of membranous bodies in the cytoplasm which accept stain and at low resolution could be misinterpreted as centrioles. The application of the electron microscope in the hands of many others^2,3, as well as more recently by us^4,5, has demonstrated that a classical form of mitotic division in these organisms cannot occur. Details of the ultrastructure of bacteria are now becoming resolved, and what is presently known precludes the possibility of a classical mitotic mechanism.