Characterization of Two Temperate Lactobacillus paracasei Bacteriophages: Morphology, Kinetics and Adsorption

MERCANTI, D.; ACKERMANN, H.-W.; QUIBERONI, A.

INTERVIROLOGY

KARGER

Lugar: Basel; Año: 2015 p. 49 - 56

0300-5526

Background/Aims: Adsorption and kinetic parameters, latent period, burst size and burst time, are characteristics of phage/host systems and can be affected by several environmental factors. As only few studies have focused on temperate dairy phages, we characterized these parameters ontemperate Lactobacillus paracasei phages i Lp 84 and  i Lp 1308, infective for probiotic strains. Methods: Phages were characterized by transmission electron microscopy and genomic DNA restriction. Adsorption under different environmental conditions, phage kinetics and efficiency of plating (EOP) were determined using the double-layer titration method. Results: Phages i Lp 84 and  i Lp 1308 belong to the Siphoviridae family and have genome sizes of 38 and 34 kbp, respectively. Adsorption was affected by calcium concentration, pH, temperature and host viability, and reached a limit at very high multiplicity of infection. Latency, burst time and burst size were of 85 min, 131 min and 46 for i Lp 84, and 51 min, 92 min and 28 for i Lp 1308, respectively, at 37 ° C. A clear influence of temperature on phage kinetics was observed. Regarding EOP, i Lp 84 produced plaques on only 1 out of 8 strains tested. Conclusion: Noticeable differences in adsorption, kinetics and EOP were found for two morphologically identical temperate L. paracasei phages of similar origin.