Conditional mutations involving septum formation in XXXX .

@entity3141 @entity7884 @entity526
The @entity7884 (-) mutation is responsible for a defect in cell division of @entity526 lightly irradiated with ultraviolet light (UV). These @entity7884 (-) mutants can be isolated readily by a procedure described here. Physiological studies were performed with the objective of determining the role of the @entity7884 gene. Unirradiated @entity7884 (-) mutants grow normally, except that a correlation of this mutation with capsule formation has been noted previously. These two properties can be separated, however. After irradiation, @entity7884 (-) grows as long filaments because septum formation is prevented. The filaments eventually lyse. Mass increase and @entity3141 and enzyme synthesis appear to proceed normally. Thus, the lesion produced by UV appears to be highly specific. In bacteria that carry both genes (merozygotes), @entity7884 (+) is dominant to @entity7884 (-). Septum formation is restored to irradiated @entity7884 (-) bacteria by introduction of @entity7884 (+) by conjugation. Also, normal growth can be restored by nutritional variations. It is concluded that @entity7884 (+) is able to nullify the effects of the UV lesion under conditions where @entity7884 (-) cannot. Possibly, capsule precursors that can accumulate in the latter are responsible for the difference because they interfere with repair of the UV lesion.
