Fig. 4.

Morphology of A. tumefaciens and E. coli grown in carbenicillin. (A) Agrobacterium grown in Cb expands at the midcell (bright-field image). (B) Fluorescence image of A: Neither the region of midcell expansion nor the growth pole label with FM 4-64, whereas the region in-between does label (arrowheads). (A and B, Insets) Close-up of a cell with midcell expansion. (C) Scanning electron micrograph shows midcell expansion is circumferential and sometimes appears to be constricting (arrow). (D) E. coli elongate but do not expand at the midcell when grown in Cb. (Scale bars, 2 μm.)