The mode of segregation of the bacterial cell membrane.

The distribution of phospholipids from labeled parental membranes to progeny cells was studied by autoradiography and a minicell system. The minicell experiments showed that, during growth, the parental membrane is diluted at the same rate in cells and in minicells, which indicates that ends of cells are not different from the cylindrical portions with regard to the distribution of parental molecules. The same result was obtained after labeling heme-containing proteins with delta-aminolevulinic acid. The autoradiographic experiments indicate that the membrane segregates in about 250 subunits 4 x 10(4) nm(2) in size. These subunits appear to be conserved during growth.