Transduction of a freshwater microbial community by a new Pseudomonas aeruginosa generalized transducing phage, UT1

Abstract

A pseudolysogenic, generalized transducing bacteriophage, UT1, isolated from a natural freshwater habitat, is capable of mediating the transfer of both chromosomal and plasmid DNA between strains of Pseudomonas aeruginosa. Several chromosomal alleles from three different P. aeruginosa strains were found to transduce at frequencies from 10(-8) to 10(-10) transductants per PFU at multiplicities of infection (MOI) between 0.1 and 1. Transduction frequencies of certain alleles increased up to 1000-fold as MOIs were decreased to 0.01. UT1 is also capable of transducing plasmid DNA to indigenous populations of microorganisms in natural lake-water environments. Data obtained in this study suggest that environmentally endemic bacteriophages such as UT1 are formidable transducers of naturally occurring microbial communities. It should be possible to develop model systems to test transduction in freshwater environments using components derived exclusively from these environments.

The Pseudomonas aeruginosa generalized transducing phage φPA3 is a new member of the φKZ-like group of ‘jumbo’ phages, and infects model laboratory strains and clinical isolates from cystic fibrosis patients

“…No differences in transduction efficiency were observed (data not shown). Transduction efficiencies were in many cases 100-fold higher than those observed elsewhere with the P. aeruginosa transducing phages DMS3, F116 and UT1 (Budzik et al, 2004;Morrison et al, 1978;Ripp et al, 1994). Therefore, for functional genomics programmes, QPA3 could serve as a powerful tool for facile and rigorous P. aeruginosa strain construction.…”

“…Several P. aeruginosa generalized transducing phages infecting PAO1 and PA14 (two of the most widely used model strains in the study of Pseudomonas infections) have been described (Budzik et al, 2004). However, DMS3, F116 and UT1 transduction efficiencies can be low, and a broad host range has not been established, so additional P. aeruginosa transducing phages are needed (Budzik et al, 2004;Morrison et al, 1978;Ripp et al, 1994). This new phage, QPA3, has for some markers a 100-fold higher transducing frequency than those of DMS3, F116 and UT1 (Budzik et al, 2004;Morrison et al, 1978;Ripp et al, 1994).…”

“…However, DMS3, F116 and UT1 transduction efficiencies can be low, and a broad host range has not been established, so additional P. aeruginosa transducing phages are needed (Budzik et al, 2004;Morrison et al, 1978;Ripp et al, 1994). This new phage, QPA3, has for some markers a 100-fold higher transducing frequency than those of DMS3, F116 and UT1 (Budzik et al, 2004;Morrison et al, 1978;Ripp et al, 1994). Thus, QPA3 is a powerful tool for the creation and study of chromosomal mutations in this pathogen.…”

“…Several P. aeruginosa generalized transducing bacteriophages have been described, though the transduction efficiency of these bacteriophages, in particular DMS3, UT1 and F116, can be very low (Budzik et al, 2004;Kidambi et al, 1994;Ripp et al, 1994). Given such low transduction efficiency, occasional background spontaneous mutants can be problematic and strain constructions need to be rigorously policed.…”

Gene Technology and Gene Ecology of Infectious Diseases

“…Horizontal gene transfers have been directly demonstrated between bacteria in the marine environment (30,131,132), in the freshwater environment (133), and in the soil (134). Again, in all the experiments, horizontal gene transfers were mediated by specially constructed hybrid plasmid vectors, of the sort used in genetic engineering.…”