FLOW-CYTOMETRY STUDIES OF RECOMBINANT ESCHERICHIA-COLI IN BATCH AND CONTINUOUS CULTURES - DNA AND RNA CONTENTS, LIGHT-SCATTER PARAMETERS

Flow cytometry has been used to study the contents of macromolecular c ompounds and light-scatter parameters in batch and continuous cultures of a recombinant Escherichia coli strain that forms protein inclusion bodies. Changes in relative DNA and RNA contents and cell mass as est imated by forward-angle light scatter were detected and tightly correl ated in batch culture. In addition, heterogeneity of wide-angle light scatter (WALS), which we related to the presence of cellular inclusion bodies, was observed. In contrast, the relative RNA content and cell mass did not change during continuous culture, and homogeneity of WALS was found. In addition, unexpected changes in relative DNA content we re observed after 67 h of culture, indicating a change in bacterial ph ysiology.