Structural instability of small rolling circle replication plasmids from Selenomonas ruminantium

Area of Science:

• Microbiology
• Molecular Biology
• Genomics

Background:

• Selenomonas ruminantium is a key rumen bacterium.
• Plasmids play vital roles in bacterial adaptation and evolution.
• Rolling circle replication (RCR) is a common plasmid replication mechanism.

Purpose of the Study:

• To determine the complete nucleotide sequence of the pSRD192 plasmid from S. ruminantium.
• To investigate the variability of pSRD192-like plasmids.
• To characterize novel pSRD192-like plasmids.

Main Methods:

• DNA sequencing of pSRD192 plasmid.
• Polymerase Chain Reaction (PCR) for variability analysis.
• Sequence comparison and characterization of related plasmids.

Main Results:

• The pSRD192 plasmid is 2334 bp and replicates via rolling circle replication.
• A variant plasmid, pSRM22 (2338 bp), was detected and characterized.
• pSRD192 and pSRM22 share identical rep genes and origins of replication with pONE429.
• Sequence comparisons revealed interspersed regions of similarity and divergence among the plasmids.

Conclusions:

• pSRD192 and pSRM22 are RCR plasmids in S. ruminantium.
• These plasmids exhibit structural instability due to interspersed sequence similarities and divergences.
• The findings contribute to understanding plasmid dynamics in S. ruminantium.