Expression of the translational sspJ-lacZ fusion in various spo mutants. Strains with a PY79 background were sporulated by the resuspension method, and β-galactosidase was assayed as described in Materials and Methods. Time 0 is when sporulation was initiated. The symbols used for the various strains are as follows. (A) •, IB475 (spo+); ▵, IB474 (spoIVCB), (B) □, IB471 (spoIIAC); ■, IB472 (spoIIGB); ○, IB473 (spoIIIG).