medium by the assay of the LacZ activity of the mutants and Northern hybridization using RNA from the wild type cell is underway. So far examined, expression at some stage of the growth has been detected in most of ORFs in the region downstream of oriC and in about half of them in the region upstream of oriC. We have observed that 6 knockout mutants showed reduced growth rate, one of which also showed sporulation defect, and two other routants only sporulation defect. In addition, one ORF was transcribed only in the sporulation phase, and the expression of some spore coat proteins was affected in its knockout mutants. Simple plate assays for utilization of several carbon and nitrogen sources, sensitivity to stresses and inhibitors, and change in secretion and motility have been carried out, and we observed some phenotypic change in 8 mutants. We also analyzed the cell morphology and the chromosome distribution by fluorescence microscopy, and found abnormal chromosome distribution in 2 mutants. The expression of the adjacent gene was affected in the two mutants of probable DNA binding protein. Thus, among 112 mutants analyzed, we could found some phenotypic changes meaningful for further specific characterization in 23% of them (26 mutants).
