Fig 1.
Inactivation & fitness suppression of OMKO1 by thermal stress.
A. To measure phage particle survival of heat stress at different temperatures, OMKO1 was exposed to one of a range of temperatures for 5, 30, 60, or 90 minutes, then titered. Percent survival is plotted relative to the titer of the 55°C treatment after 0 minutes. The dotted line denotes the limit of detection, with the timepoint where survival fell below the limit of detection plotted as an asterisk. 80°C was also tested but caused such rapid particle decay that all measures fell below the limit of detection. B. To measure phage particle survival of heat stress over longer periods of time, five biological replicates of phage OMKO1 were exposed to 70°C for 5, 90, 180, 270, or 360 minutes, then titered. Percent survival is plotted relative to the source stock titer. The dotted line denotes the mean limit of detection across all five batches. C. To determine whether phage fitness is affected by a history of heat stress exposure, 70°C heat shocked phages or unshocked control phages (0 min) were inoculated with bacteria and grown overnight while measuring bacterial density. As a metric of phage fitness, the peak bacterial density was computationally determined. Thus, higher peak bacterial densities indicated phages with lower fitness. The dotted line denotes the absence of bacterial growth. Bacteria were also grown in the absence of phage in LB media (“+ Ctrl”) or LB media that had been heat shocked for 360 mins at 70°C (“+ Ctrl Shock”). Heat shock treatments that are not significantly different from each other via Tukey Honest Significant Differences are indicated by the same shared letter (a or b).
Table 1.
Multiple regression shows significant phage OMKO1 decay at 65°C and higher temperatures.
Fig 2.
Phage OMKO1 decay is not accelerated by saline concentration.
Fig 3.
Degradation of phage OMKO1 under different urea concentrations.