Table 1.

Numbers of selected colonies with active and inactive ribozymes on TMP-containing and/or ampicillin-containing plates

Ribozyme	TMP plate	Ampicillin plate
G5 and A5 mixture
Active ribozyme	75	29
Inactive ribozyme	1	28
A14 and G14 mixture
Active ribozyme	42	21
Inactive ribozyme	2	9

Plates were incubated at 27°C for 2–3 days, then larger colonies were picked up at random. TMP plates contained 70 μg of TMP and 100 μg of ampicillin per milliliter, and ampicillin plates contained 100 μg of ampicillin per milliliter without TMP.