Bacillus anthracis harbors two plasmids, designated pXO1 and pXO2, which are involved in the synthesis of toxin and capsule. Proof that pXO1 and pXO2 are involved in the synthesis of toxin and capsule, respectively, came from experiments in which the plasmids were transferred by the Bacillus thuringiensis subsp. thuringiensis fertility plasmid, pXO12. The number of transcipients acquiring either pXO1 or pXO2 was low when compared to the number of transcipients that acquired pBC16. Plasmids pXO1 and pXO2 that had been transferred were shown to have acquired a 4.2-kb transposon which is related to the B. thuringiensis transposon Tn4430. The transposon, Tn4430, appears to be responsible for the formation of cointegrate plasmids necessary for pXO12-mediated transfer of pXO1 and pXO2. Putative cointegrate plasmids were obtained between pXO12 and the B. anthracis plasmids, pXO1 and pXO2. Strains harboring cointegrate plasmids were shown to be capable of transferring pBC16, and also transferred the PA$\sp+$ and Cap$\sp+$ phenotypes at high frequencies. Experiments using a pXO12 plasmid tagged with the Streptococcus faecalis transposon, Tn917, showed that this transposon was also capable of forming a cointegrate between pXO2 and pXO12::Tn917. In contrast, pBC16 was unchanged after transfer, and showed no homology to pXO12. Mobilization of the resident B. anthracis plasmids was shown to occur by conduction, while mobilization of the small tetracycline-resistance plasmid pBC16 appeared to occur by donation.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-7498 |
| Date | 01 January 1988 |
| Creators | Green, Brian Douglas |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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