FIG 4.

A minC::Kan^r mutation results in aberrant cell division in liquid culture. The cell division phenotypes for wild-type strain PM7002 (top), PMKH1 (PM7002 minC::Kan^r) (middle), and PMKH5 (PM7002 minC::Kan^r plus pMinCDE) (bottom) are shown. Cells were grown to mid-log phase, and 1.5 μl was imaged using phase-contrast microscopy. Liquid cultures of PM7002 exist as rod-shaped cells, often as doublets, with septa positioned at the centers of the cells. The minC::Kan^r mutation causes a large percentage of the cells to divide at the poles (middle image, insets). Minicells are often present. The division phenotype can be complemented by the addition of minCDE in single copy (bottom). The images were taken at ×1,000 magnification. All cell sizes in the insets have been increased equally.