The biological characterization of Pseudomonas aeruginosa phage PaP3 / 解放军医学杂志

ABSTRACT

Objective To identify some basic biological properties,optimal multiplicity of infection(MOI),one-step growth kinetics,serum neutralization rate constant of Pseudomonas aeruginosa phage PaP3 were determined, respectively. Methods The host bacteria were infected with PaP3 at six different MOI(0.0001,0.001,0.01,0.1,1 and 10,then lysated adequately, the phage titer of supernatant was determined.For one-step growth experiments,the host bacteria were infected with PaP3 at MOI=10, following centrifugation after 15 min adsorption,the pellet containing (partially) infected cells was resuspended in 3 ml of pre-warmed LB broth and incubated with 160rpm at 37℃.Samples(50?l) were taken at 10 min-intervals and immediately tittered by the double-layer agar plate method. A rabbit was immunized with purified PaP3 to prepare anti-PaP3 serum, reaction constants between antiserum and PaP1, PaP2, PaP3 were determined using cross neutralization test. Results 0.001 MOI-infected host bacteria gave the highest phage offsprings. One-step growth curve was determined according to the results of one-step growth experiments.Reaction constant was determined using neutralization test. Conclusion The optimal MOI of PaP3 was determined to be 0.001. One-step growth curve for PaP3 shows that the latent period is about 20 min, the rise period is 60 min, and the average burst size is about 31pfu/cell. Rate constant of reaction between antiserum and PaP3 is 262.