Mobilization of the Proteus morganii chromosome by R plasmids

Area of Science:

• Microbiology
• Bacterial Genetics
• Molecular Biology

Background:

• R plasmids are known to mediate horizontal gene transfer.
• The ability of R plasmids to mobilize bacterial chromosomes varies.
• Proteus morganii is a bacterium relevant in clinical settings.

Purpose of the Study:

• To investigate the chromosomal mobilization capabilities of various R plasmids in Proteus morganii.
• To determine if specific R plasmids can act as sex factors for chromosome transfer in this species.
• To analyze the inheritance patterns of chromosomal markers during mobilization.

Main Methods:

• Conjugation experiments were performed using Proteus morganii 2815 as the donor strain.
• Several R plasmids from different incompatibility groups were introduced into the donor.
• Matings were conducted with doubly auxotrophic recipient strains using R711b or R702 as mobilizing plasmids.

Main Results:

• Multiple R plasmids (R702, R711b, R1, D, Rip69, R447b, R471, R394) demonstrated the ability to mobilize the Proteus morganii chromosome.
• Recombinants obtained through mating with R711b or R702 showed the obligatory inheritance of the ser-1+ marker.
• The inheritance of the ser-1+ marker was independent of other selected markers.

Conclusions:

• Various R plasmids can effectively mobilize the Proteus morganii chromosome.
• R plasmids R711b and R702 are efficient sex factors for chromosome transfer in this bacterium.
• The ser-1+ locus is consistently co-inherited during mobilization mediated by these R plasmids.