The activity of the succinic dehydrogenase system was studied in Escherichia coli utilizing combined techniques of cytochemistry and electron microscopy. Organisms were incubated in a medium containing tetranitro-blue tetrazolium (TNBT) which served as an electron acceptor. Enzymatic activity, as evidenced by the deposition of aggregates of TNBT-formazan, was found associated with the site of the plasma membrane of the bacterium.

This content is only available as a PDF.