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[Some developmental features of Escherichia coli Mu phage in Pseudomonas aeruginosa cells]
Abstract:
In order to determine the replication-transposition (RT) efficiency of Escherichia coli phage Mu in Pseudomonas aeruginosa cells, the change of Mu DNA copy number after transfer of P. aeruginosa (RP4::Mu) from 42 (the condition of RP4::Mu plasmid stability and low phage production level in P. aeruginosa) to 30 degrees C (the condition of RP4::Mu plasmid instability and higher phage production level in P. aeruginosa) was analysed. It was shown that the temperature shift causes no increase in Mu DNA copy number, although free phage DNA is revealed after transfer of the cells at 30 degrees C. Considering that the studied cells contained also a linear RP4 DNA and the free Mu DNA hybridized with the RP4 DNA, we proposed that the mature Mu DNA arises as a result of Mu genome packaging from the original plasmid. So, the Mu genome RT is uneffective in P. aeruginosa and all of the phage particles released from P. aeruginosa (RP4::Mu) cells contain Mu DNA apparently originated from the DNA of hybrid plasmid RP4::Mu. Moreover, these results suggest that the Mu DNA packaging is not effective in P. aeruginosa (taking into account that the P. aeruginosa (RP4::Mu) cells release about 10(-2) p.f.u./cell and that originally the copy number of RP4::Mu > or = 1).
Insights
Escherichia coli phage Mu exhibits ineffective replication-transposition (RT) in Pseudomonas aeruginosa. Phage particles released contain Mu DNA originating from the RP4::Mu hybrid plasmid, not from efficient RT.
Area of Science:
- Microbiology
- Molecular Biology
- Bacteriology
Background:
- Escherichia coli phage Mu is a model organism for studying replication-transposition (RT).
- Pseudomonas aeruginosa is an opportunistic pathogen with clinical relevance.
- Understanding phage-host interactions is crucial for phage therapy and genetic engineering.
Purpose of the Study:
- To determine the replication-transposition (RT) efficiency of phage Mu in Pseudomonas aeruginosa.
- To investigate the origin of phage Mu DNA in P. aeruginosa.
- To analyze the impact of temperature shifts on phage Mu DNA replication and production.
Main Methods:
- Culturing P. aeruginosa with the RP4::Mu hybrid plasmid at different temperatures (42°C and 30°C).
- Analyzing changes in Mu DNA copy number using hybridization techniques.
- Detecting free phage DNA and assessing phage particle release (p.f.u./cell).
Main Results:
- A temperature shift from 42°C to 30°C did not increase Mu DNA copy number in P. aeruginosa.
- Free phage DNA was detected at 30°C, hybridizing with RP4 DNA, suggesting packaging from the plasmid.
- Phage particle release was low (10^-2 p.f.u./cell), indicating ineffective Mu DNA packaging and RT in P. aeruginosa.
Conclusions:
- Replication-transposition of phage Mu is ineffective in Pseudomonas aeruginosa.
- Mature Mu DNA in released phage particles originates from the RP4::Mu hybrid plasmid.
- Mu DNA packaging is inefficient in P. aeruginosa, limiting phage production.