UMBC Biol302L: Genetics Lab

              Streptomycin is an antibiotic interfering with binding of 30S subunit. Streptomycin prevents bacterial growth by inhibiting protein synthesis. A mutant must be altered at rpS12 in order to withstand the streptomycin. Culture of wild type E. coli W3110 was used as a bacteria which would be mutated to streptomycin. After counting viable colonies, the frequency of spontaneous mutations was calculated to be 3.44 * 10^ -10 mutants/cfu.

              Streptomycin resistance or dependence is resulted in mutation in rspL gene. This certain mutant phenotype was identified to be streptomycin resistant. It is determined by transferring mutant strain on to a TBAB with streptomycin and TBAB alone. Streptomycin resistant mutants would be spotted on both of plates. Meaning mutant can live without streptomycin. Then, the streptomycin dependent mutants would only be spotted on TBAB with streptomycin. Which concludes that dependent mutant can not survive without streptomycin. The amplified rpsL gene of wild type E. coli is then sequenced for comparison with other species.