Abstract
SUMMARY: Changes in Mycobacterium phlei due to B2h lysogeny were studied by the replica plating method. The changes could be divided into three categories: mutation to slow growth and small colony size; mutation to relative but complex nutritional requirements; and finally mutation to thiamine deficiency (thi-). A segregant clone obtained in the thi- mutant showed the characteristics of slow-growing small colony variants. Change in the bacterial host could be related to the type of integrated phage.