Abstract
PA26, a novel lytic bacteriophage infecting Pseudomonas aeruginosa, was isolated, and the whole genome was sequenced. It was found to belong to the myoviridae by an electron microscopic observation. It had a linear double-stranded DNA genome of 72,321 bp. Genomic analysis showed that it resembled another Pseudomonas phage, LIT1.
GENOME ANNOUNCEMENT
Pseudomonas aeruginosa is a Gram-negative bacterium that acts as an opportunistic pathogen. It forms biofilms (6) relating to infections in cystic fibrosis patients (3) and burn wound patients (1). An increasing incidence of multidrug-resistant strains has been reported (2). Bacteriophages were used to control multidrug-resistant Pseudomonas aeruginosa strains (5).
We isolated PA26 from a water reservoir in Naju City, South Korea. The host strain used for isolation and propagation of the phage was Pseudomonas aeruginosa ATCC 27853. The infection was strictly lytic. The phage infected other strains of Pseudomonas aeruginosa, including ATCC 15522, ATCC 10145, ATCC 9027, ATCC 25619, ATCC 13388, and ATCC 15692.
The phage DNA was isolated using a Phage DNA isolation kit (Norgen Biotech, Canada). Whole genomic DNA was sequenced in a Roche 454 genome sequencer, and data processing was done using Roche GS FLX software (v2.6) (Macrogen, South Korea).
The genomic DNA of phage PA26 was a linear double strand 72,321 bp in length. Its G+C content was 54.82%. There were 88 predicted open reading frames (ORFs), of which 14 had putative functions. Structural proteins included coat protein, putative tail protein, putative tail fiber protein, and putative portal protein, while nonstructural proteins included a putative DNA helicase, putative RNA polymerase, NHN endonuclease, putative rIIA-like protein, putative rIIB-like protein, and putative single-strand binding protein. The remaining 74 were hypothetical proteins.
Although PA26 showed sequence similarities with LIT1, its morphology is quite different. LIT1 belongs to the podoviridae with short tails (4), while PA26 belongs to the myoviridae. LIT1 has two putative tail proteins. ORF56 of LIT1 shows very high similarity to that of PA26, but ORF53 showed decreased similarity (only 63% query coverage and 74% identity) to that of PA26. The latter ORF could be the reason the two phages have tails of different lengths.
Nucleotide sequence accession number.
The complete genome sequence of Pseudomonas aeruginosa phage PA26 is available in GenBank under accession number JX194238.
ACKNOWLEDGMENT
This study was supported by HUFS research fund of 2012.
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