Submitted to: International Conference on Microbial Genomes
Publication Type: Abstract Only
Publication Acceptance Date: 9/26/2004
Publication Date: 9/30/2004
Citation: Porwollik, S., Frye, J.G., Cheng, P., Blackmer, F., Mcclelland, M. 2004. Detection of phage activity and resulting escape replication in salmonella by microarray. International Conference on Microbial Genomes.
Technical Abstract: Salmonella enterica genomes usually contain one or more integrated prophage. However, using conventional methods it is difficult to ascertain which of these phage genomes can become active and under what conditions. Phage genome replication of the four temperate functional prophages from Typhimurium LT2 was studied by microarray analysis of total DNA after induction using peroxide or mitomycin C. All four phage were observed to be induced. A large amplification of host DNA, “escape replication”, spanning several hundred genes, was detected adjacent to the integration site of the Fels-1 lambdoid phage. Regions of host genome amplification were also observed in Typhimurium strain 14028s indicating integration sites of phage, the genes of which were not included in the microarray. Escape replication and possibly resulting escape synthesis (changes in expression of RNA from amplified host genes) may have an impact on transduction, recombination, and host response to stresses. Microarray analysis of phage particles harvested from the supernatants of induced cultures indicated that even after escape replication, phage are mostly packaged correctly. Using mitomycin C or peroxide as an inducer, activity of at least one prophage was also detected in S. enterica serovars Paratyphi A SARB42 and Enteritidis PT4, but not for any of the prophage genomes present in Typhi CT18. In summary, microarray analysis revealed the extent of escape replication for several phages in Typhimurium, and allowed activation of phage to be monitored in different Salmonella.