A coupling process for improving purity of bacterial minicells by holin/lysin

Drug and gene delivery systems using bacterial minicells have attracted much attention. Here we attempted to enhance the yield and purity of the minicells using a novel method in which autolysin induced in actively metabolizing parent cells led to autolysis. A two-step protocol coupling an autolysin (holin/lysin) step with a conventional centrifugation step achieved a purity of the minicells similar to that resulting from successive six- or seven-step methods.     

Molecular cloning of the plasmids of Vibrio cholerae 01 and the incidence of related plasmids in clinical isolates and other Vibrio species

Abstract We describe the subcloning of plasmids present in Vibrio cholerae 01 strain V58: the P factor, the large cryptic plasmid (lcp) and small cryptic plasmid (scp). Strains harbouring fragments of the P sex factor and the lcp were examined for plasmid encoded proteins by Coomassie blue staining and analysis in Escherichia coli K-12 minicells.
The distribution of these three plasmids in a variety of Vibrio species has been examined using some of the cloned fragments as DNA probes. Most recent clinical isolates of V. cholerae were found to contain the scp. None of the strains contained the lcp. The P factor was only detected in one clinical isolate in addition to the scp. While plasmids appear to be generally uncommon among V. cholerae , and do not appear to differentiate biovars, the presence of plasmids may be a useful epidemiological adjunct.