Figure 7.

Effects of disruption of yvyD and spo0H genes on cell proliferation and ribosome formation. (A and B) Cell proliferation. Growth profiles of (A) yvyD gene disrupted strain RIK1070 (aprE::Pspac-ywaC relA::erm ΔyjbM ywaC::cat yvyD::PrrnOkan) and (B) spo0H gene disrupted strain RIK1089 (aprE::Pspac-ywaC relA::erm ΔyjbM ywaC::cat spo0H::tet) in LB medium. Cells were inoculated in LB medium and grown at 37°C with shaking. When the OD₆₀₀ reached ca. 0.2 (indicated by arrow), 1 mM IPTG (final concentration) was added to the culture and the OD₆₀₀ of the culture was monitored: (?) cells treated with IPTG (○) untreated cells (control). (C) Ribosome formation. Sedimentation profiles of sucrose density gradients of IPTG-induced and uninduced cells. Crude cell extracts were prepared from IPTG-induced and uninduced RIK1070 and RIK1089 cells and the cell extracts were then sedimented through a 10–40% sucrose gradient as described in the Section Experimental procedures.