Conjugation systems of IncT plasmids.

Four IncT plasmids were compared for various characters, in particular pilus synthesis and function at different temperatures. The prototype Rts1 differed in some respects from the others (R402, R394, pIN25). At 37 degrees C, the supposedly temperature-sensitive conjugation systems of the plasmids could still function efficiently on a surface, but not in a liquid. Long conjugative pili were synthesized at 30 degrees C, but only short ones (approx. 200 nm) were produced at 37 degrees C. The long pili converted two surface-obligatory conjugation systems to surface + liquid ones at 30 degrees C.