Following growth for 2 days, colonies were replica plated onto MM

Following growth for 2 days, colonies were replica plated onto MM agar to screen for auxotrophs. Electron microscopy MAPK inhibitor of filtered culture supernatants was carried out as described by Petty et al. (2006), but staining with uranyl acetate. The Pa genome sequence (GenBank accession number BX950851) was viewed with artemis (Rutherford et al., 2000). Prophage genomes were compared using the artemis comparison tool (Carver et al., 2005). Multiple sequence alignments were carried out using clustalw (http://align.genome.jp). Four microlitres of bacterial cultures diluted to OD600 nm 0.2 were spotted onto tryptone swarm agar (0.3% w/v Bacto agar, 1% w/v Bacto tryptone and 0.5% w/v NaCl). Halo diameters were measured after incubation

at 25 °C for 24 h. Maris Piper potatoes were surface sterilized for 10 min in 1% Virkon, and then rinsed thoroughly with deionized water. Potatoes were stab-inoculated as described by Coulthurst et al. (2006), wrapped in three layers of wet tissue and cling film and incubated at 25 °C. After 4 days, potatoes were cut open and the weight of the rot was measured. ECA41, consisting of genes ECA3695–ECA3742, shares extensive homology with the ST15 prophage, present in Salmonella enterica http://www.selleckchem.com/products/gsk1120212-jtp-74057.html serovar Typhi strains (Thomson et

al., 2004). The syntenic organization is conserved between 38 ECA41 genes and ST15. Eleven additional genes appear to have been acquired in ECA41, nine of which are of Thymidine kinase unknown function, and may be ‘cargo’ genes. Six base pair repeats (CCTCGA) were found flanking ECA41, which may indicate that the mechanism of integration is the same as that for phage Mu, which results in duplication of 5 bp of the target site sequence. Integration of ECA41 disrupts the coding

sequence of a gene, which is annotated as two separate ORFs: ECA3743 and ECA3694. Reassembly of this gene using the experimentally determined limits of the prophage, followed by psi-blast analysis predicts that it encodes a GCN5-related N-acetyltransferase, possibly a PhnO homologue involved in phosphonate metabolism in response to phosphate starvation (Errey & Blanchard, 2006). Other members of the GCN5-related N-acetyltransferase family include proteins that transfer an acetyl group to aminoglycoside antibiotics, resulting in broad-spectrum resistance (Vetting et al., 2004). ECA29 is a P2 family prophage, and includes genes ECA2598–ECA2637. Of the 41 genes, 29 have clear homologues in phage P2. The remaining 12 encode largely unknown functions, with the exception of a DNA adenine methylase. Other prophages have been shown to encode DNA adenine methylases that methylate both phage and bacterial DNA (Magrini et al., 1997) and protect the phage from restriction upon infection of new hosts. Bacterial DNA methyltransferases have also been shown to be important in the stable maintenance of lysogeny (Murphy et al., 2008) and bacterial virulence (Heithoff et al., 1999).

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