Restriction digests of the clone give the following sizes (kb): EcoRI--6.8, 2.7; HindIII--5.4, 2.6; Because resistance levels may vary, it is important to determine the proper antibiotic concentration for each strain or isolate. One of a series (ATCC 37653 through 37657) of vectors for in vitro mutagenesis (via the omega interposon) of gram-negative bacteria. An EcoRI fragment containing omega was ligated to EcoRI-digested pKT254. The spcR gene was deleted (SphI/BssHII double digest) and replaced with a 1.75 kb BamHI/BalI fragment of pKT235 containing the ampicillin resistance gene. |