Competent bacteria
View Patent ↗The present invention discloses that a bacterium having a genome that is genetically engineered to be at least 10% smaller than the genome of its native parent strain has better transformation competence. Specific E. coli strains, having significantly reduced genome sizes, are disclosed which are highly transformation competent. A medium and methodology is taught which enables transformation efficiencies to be increased further.
1. A method of preparing an Escherichia coli culture for transformation at increased efficiency as compared to E. coli K12 MG1655, the method comprising
culturing the E. coli to an optical density at 650 nm of at least 0.4 in a medium,
wherein the E. coli is an multi-deletion series strain lacking bases 263080-324632, 1398351-1480278, 2556711-2563500, 2754180-2789270, 2064327-2078613, 3451565-3467490, 2464565-2474198, 1625542-1650865, 4494243-4547279, 3108697-3134392, 1196360-1222299, 564278-585331, 15388-20563, 263080-324632, 564278-585331, 602639-608573, 1398351-1480278, 2064327-2078613, 2507650-2515969, 2556711-2563500, 2754180-2789270, 379293-387870, 389121-399029, 2992959-2996892, 3182796-3189712, 3451565-3467490, 2464565-2474198, 1625542-1650785, 4494243-4547279, 3108697-3134392, 1196360-1222299, 687074-688268, 1386912-1396646, 2099418-2135739, 2284410-2288200, 3359747-3365277, 3648921-3651343, 1128637-1140209, 1960605-1977294, 1995085-2021700, 4553059-4594581, 522062-529348, 728616-738185, 1525914-1531648, 3616623-3623309, 3759620-3767868, 1041253-1049768, 1085329-1096603, 2163172-2175230, 3578769-3582674, and 3718262-3719704 of the E. coli strain K12 MG1655.
2. The method of claim 1 , wherein the medium is Terrific Broth.
3. The method of claim 1 , wherein the culturing is done at in excess of 26° C.
4. The method of claim 1 , wherein the optical density at 650 nm is at least 0.6.
5. The method of claim 1 , wherein the optical density at 650 nm is at least 1.0.
6. The method of claim 1 , further comprising transforming the bacteria with a foreign DNA molecule.
7. The method of claim 6 , wherein the transformants recovered are in excess of 10 10 transformants per microgram of introduced DNA.