ured into sterile petri plates. The selective media was prepared so that 84 plates were made. These plates were made much in the same way as the complete plates, except that 28 of the plates contained all of the reagents except proline, another 28 were without histadine, and another 28 were without threonine. These were labeled with "pro-", "his-", and "thr-". Viable Counts: The strain used was Escherichia coli K12. The donor and recipient cultures were kept as much as possible in a water bath at 37C. Viable counts of the donor (Hfr) and recipient were done on complete MM56 and Luria agar. Serial dilutions were performed to obtain a 10-7 and 10-8 dilutions of the recipient, and 10-2, 10-7, and 10-8 dilutions of the donor. Two Luria plates were inoculated with 1 ml each of the 10-7 dilution of the recipient. Two Luria plates were inoculated with 1 ml each of the 10-8 dilution of the recipient. Two Luria plates were inoculated with 1 ml each of the 10-7 dilution of the donor. Two Luria plates were inoculated with 1 ml each of the 10-8 dilution of the donor. Two complete MM56 plates were inoculated with 1 ml each of the 10-7 dilution of the recipient. Two complete MM56 plates were inoculated with 1 ml each of the 10-8 dilution of the recipient. One complete MM56 plate was inoculated with 1 ml of the 10-2 dilution of the donor. Each of these were inoculated for 48 hours. Conjugation: 30 sterile test tubes were filled with 9 ml each of sterile saline solution. A supply of sterile top agar was kept in a water bath to keep liquid until needed. One ml of the donor culture was added to 20 ml of the recipient culture in a flask. This mating mix was kept in the 37C water bath. Immediately (0 minutes), 1 ml of the mating mix was removed from the flask and added to 9 ml of sterile saline, making a 10-1 dilution. This was placed on the vortex for 60 seconds to interrupt any mating taking place in the mix. 1 ml of this mixture was added to another tub...
