Complete Genome Sequence Analysis of Two Pseudomonas plecoglossicida Phages, Potential Therapeutic Agents

Abstract

Pseudomonas plecoglossicida is a lethal pathogen of ayu (Plecoglossus altivelis) in Japan and is responsible for substantial economic costs to ayu culture. Previously, we demonstrated the efficacy of phage therapy against P. plecoglossicida infection using two lytic phages (PPpW-3 and PPpW-4) (S. C. Park, I. Shimamura, M. Fukunaga, K. Mori, and T. Nakai, Appl Environ Microbiol 66:1416-1422, 2000, http://dx.doi.org/10.1128/AEM.66.4.1416-1422.2000; S. C. Park and T. Nakai, Dis Aquat Org 53:33-39, 2003, http://dx.doi.org/10.3354/dao053033). In the present study, the complete genome sequences of these therapeutic P. plecoglossicida phages were determined and analyzed for deleterious factors as therapeutic agents. The genome of PPpW-3 (myovirus) consisted of 43,564 bp with a GC content of 61.1% and 66 predicted open reading frames (ORFs). Approximately half of the genes were similar to the genes of the Escherichia coli phage vB_EcoM_ECO1230-10 (myovirus). The genome of PPpW-4 (podovirus) consisted of 41,386 bp with a GC content of 56.8% and 50 predicted ORFs. More than 70% of the genes were similar to the genes of Pseudomonas fluorescens phage ϕIBB-PF7A and Pseudomonas putida phage ϕ15 (podoviruses). The whole-genome analysis revealed that no known virulence genes were present in PPpW-3 and PPpW-4. An integrase gene was found in PPpW-3, but other factors used for lysogeny were not confirmed. The PCR detection of phage genes in phage-resistant variants provided no evidence of lysogenic activity in PPpW-3 and PPpW-4. We conclude that these two lytic phages qualify as therapeutic agents.

Characterization of maltocin S16, a phage tail‐like bacteriocin with antibacterial activity againstStenotrophomonas maltophiliaandEscherichia coli

“…Phage PPpW‐3 is a myoviridae phage, produced by P. plecoglossicida (Kawato et al ). Ghequire and De Mot () point out that various PTLBs likely evolved independently, and maltocin and pyocin R2 apparently originated from different ancestors.…”

“…These strains were isolated from either clinical or environmental sources in different countries, suggesting that the maltocins are not only widespread but also quite conserved among S. maltophilia strains. Phage PPpW-3 is a myoviridae phage, produced by P. plecoglossicida (Kawato et al 2015). Ghequire and De Mot (2015) point out that various PTLBs likely evolved independently, and maltocin and pyocin R2 apparently originated from different ancestors.…”

Full-genome sequence of a novel myovirus, GF-2, infecting Edwardsiella tarda: comparison with other Edwardsiella myoviral genomes

“…Phage GF-2 was isolated and purified by a method described previously [9]. Purified phages were negatively stained with 2 % uranyl acetate on an elastic carbon-coated copper grid (Okenshoji Co. Ltd., Tokyo, Japan) and imaged using a JEOL JEM-1200EX transmission electron microscope (TEM) at 80 kV as described previously [9].…”

Characterisation of a newly detected bacteriophage infecting Bordetella bronchiseptica in swine

“…Phages containing lysogen-related genes, but not being temperate themselves, have been described previously. For example, while phage UAB_Phi20 contains all the elements needed for a lysogenic cycle, phage PPpW-3 only contains an integrase gene; however, both are lytic phages [16,17].…”

“…To test for possible lysogens, host B. bronchiseptica 4715 cells in exponential growth phase (approximately 10 7 colony-forming units/ml) were incubated with phage vB_ BbrM_PHB04 at a multiplicity of infection (MOI) of 100 in SM buffer and the mixture was incubated for 10 min to allow adsorption of phages [16]. The conventional double-layer agar method was used to pick 40 random phage-resistant colonies.…”