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[Effect of TRA-system of plasmids RP4 and R68.45 on pseudomonas mallei virulence]
V V Verevkin1, N V Volozhantsev, V P Miakinina
1State Scientific Center of Applied Microbiology, Obolensk.
Abstract:
In Pseudomonas mallei, spontaneous mutants (Tra- mutants) of the plasmids RP4 and R68.45, losing the ability to transfer at conjugation are formed. The plasmids RP4 and R68.45 with Tra(+)-phenotype caused a decrease in P. mallei virulence for laboratory animals. At the same time, Tra- mutants of these plasmids do not affect P. mallei virulence. The insertion of DNA fragment of about 1900 bp into the plasmid transfer gene regions (tra-2-tra-3) gave rise to RP4 and R68.45 tra mutations detectable on examination.
Insights
Spontaneous mutations in Pseudomonas mallei plasmids RP4 and R68.45 (Tra- mutants) eliminate transfer ability and restore virulence. Wild-type plasmids (Tra+) reduce virulence, indicating plasmid transfer affects bacterial pathogenicity.
Area of Science:
- Microbiology
- Bacterial genetics
- Plasmid biology
Context:
- Pseudomonas mallei is an important animal pathogen.
- Plasmids RP4 and R68.45 are conjugative plasmids.
- Plasmid transfer can influence bacterial virulence.
Purpose:
- To investigate the role of plasmid transfer in Pseudomonas mallei virulence.
- To characterize spontaneous plasmid mutants affecting transfer ability.
Summary:
- Spontaneous Tra- mutants of plasmids RP4 and R68.45 were generated in P. mallei.
- These Tra- mutants did not affect P. mallei virulence.
- Wild-type Tra+ plasmids decreased P. mallei virulence.
- Insertion of a DNA fragment into transfer genes created detectable tra mutations.
Impact:
- Plasmid transfer, not the mere presence of the plasmid, influences P. mallei virulence.
- This finding has implications for understanding bacterial pathogenesis and developing novel control strategies.