Bacillus subtilis BSA 170 trp- ura-: un nuevo mutante nutricional con requerimientos absolutos de triptofano y uracilo exógenos para su crecimiento. / [Bacillus subtilis BSA 170 trp- ura-: a new nutritional mutant with absolute requirements for exogenous tryptophan and uracil for its growth]

ABSTRACT

A new Bacillus subtilis mutant was prepared, with a double nutritional requirement for uracil and tryptophan. The mutant, designed Bacillus subtilis BSA 170 trp- ura-, was constructed by transformation method, acting B. subtilis strain PB 168 trp- as recipient and B. subtilis strain PB 3308 ura- as transforming DNA donor cells. The BSA 170 trp- ura- strain was selected by replication of transformed population on nutritionally selective media. Competence development induction and genetic markers transformability were tested. The new mutant was competent by Young and Spizizens methodology. Furthermore, both markers, uracil and tryptophan, may be transformed when B. subtilis BSA 170 trp- ura- competent cells are treated with transforming DNA isolated from B. subtilis PB 19, prototroph. Transformation frequency rate for each marker alone was far larger than that reached for both taken together.