Homospecific and heterospecific transformation with chimeric plasmid DNA in Haemophilus influenzae and Haemophilus parainfluenzae

Abstract

A gene for resistance to novobiocin has been self-cloned in H. parainfluenzae, using a high-efficiency plasmid vector pJ1-8: Homospecific and heterospecific transformation using chimeric plasmids containing an insert of the nov^r gene of H. influenzae or H. parainfluenzae has revealed some novel features. There is some evidence from our observations that H. parainfluenzae also recognises specific uptake sites in the incoming DNA. Transformation with chimeric and non-chimeric plasmids suggests that the homology of the insert to the resident DNA has a major role in the extrachromosomal fixation of chimeric plasmids. It is also inferred that apart from the (passive) internalisation of input DNA from transformasomes, there is also recombination-assisted internalisation.