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Updated: Jun 24, 2026
Tools for the Real-Time Assessment of a Pseudomonas aeruginosa Infection Model
Published on: April 6, 2021
ParB deficiency in Pseudomonas aeruginosa destabilizes the partner protein ParA and affects a variety of
A A Bartosik1, J Mierzejewska1, C M Thomas2
1Institute of Biochemistry and Biophysics, PAS, 02-106 Warsaw, Pawinskiego 5A, Poland.
Abstract:
Deletions leading to complete or partial removal of ParB were introduced into the Pseudomonas aeruginosa chromosome. Fluorescence microscopy of fixed cells showed that ParB mutants lacking the C-terminal domain or HTH motif formed multiple, less intense foci scattered irregularly, in contrast to the one to four ParB foci per cell symmetrically distributed in wild-type P. aeruginosa. All parB mutations affected both bacterial growth and swarming and swimming motilities, and increased the production of anucleate cells. Similar effects were observed after inactivation of parA of P. aeruginosa. As complete loss of ParA destabilized its partner ParB it was unclear deficiency of which protein is responsible for the mutant phenotypes. Analysis of four parB mutants showed that complete loss of ParB destabilized ParA whereas three mutants that retained the N-terminal 90 aa of ParB did not. As all four parB mutants demonstrate the same defects it can be concluded that either ParB, or ParA and ParB in combination, plays an important role in nucleoid distribution, growth and motility in P. aeruginosa.
Insights
ParB protein is crucial for Pseudomonas aeruginosa nucleoid distribution, growth, and motility. Its absence or partial removal disrupts cell division, leading to anucleate cells and affecting bacterial movement.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Genetics
Background:
- The ParABS system is essential for bacterial chromosome segregation.
- ParB is a key component involved in partitioning bacterial DNA.
- Understanding ParB's role in Pseudomonas aeruginosa is vital for bacterial cell biology.
Purpose of the Study:
- To investigate the function of ParB in Pseudomonas aeruginosa.
- To determine the impact of ParB deletions and domain mutations on bacterial physiology.
- To elucidate the relationship between ParA and ParB in P. aeruginosa.
Main Methods:
- Introduction of deletions and domain mutations in the ParB protein.
- Fluorescence microscopy to visualize ParB foci distribution.
- Assessment of bacterial growth, motility (swarming and swimming), and anucleate cell production.
Main Results:
- ParB mutants lacking C-terminal domains or HTH motifs showed irregular foci distribution.
- All parB mutations impaired bacterial growth, motility, and increased anucleate cells.
- Complete ParB loss destabilized ParA, while partial loss did not.
Conclusions:
- ParB plays a significant role in nucleoid distribution, growth, and motility in P. aeruginosa.
- The observed defects suggest a combined role for ParA and ParB in these processes.
- Specific domains of ParB are critical for its proper function and interaction with ParA.
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